JPH06275935A - Circuit pattern in flexible board - Google Patents

Abstract

PURPOSE:To obtain a circuit pattern in a flexible board which enables attainment of the same effect as produced by resistors and capacitors being mounted, without mounting these electric components, for stabilizing a power line and preventing a false operation of a signal line for control due to external noise. CONSTITUTION:A flexible board is made to have a multilayer structure by using a polyimide film and a pattern part 106 having a large area partially is formed in a part of a pattern 101 for a power line. A counter electrode layer is formed on the opposite side to this pattern part 106 with the polyimide film held between, and thereby a capacitor is formed with the polyimide film used as a dielectric. In a signal line 102 for control, pattern parts 105a to 105g having large areas are formed partially likewise so that they hold pattern parts of small areas between them, and thus a noise filter is constructed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board pattern formed by using a flexible board.

[0002]

2. Description of the Related Art Conventionally, in an electric circuit board, in order to cope with external noise such as power line noise and electrostatic noise, the power line in the pattern on the board or the signal line is stabilized, The following measures were used for protection.

1) A capacitor having a large capacity is mounted between the power line pattern and the GND line pattern.

2) A capacitor is mounted between the control signal line pattern and the power supply line pattern or the GND line pattern.

3) Elements such as capacitors and resistors are mounted to form a noise filter corresponding to the frequency of external noise to be removed.

[0006]

However, in the above-mentioned conventional example, there are the following drawbacks in order to stabilize the power supply line and to prevent malfunction due to external noise in the control signal line.

1) A large space is required to mount the capacitor.

2) A space for mounting a resistor or a capacitor for forming a filter is required.

3) Especially, in the narrow space, the advantage of using the flexible substrate cannot be effectively used for the above 1 and 2).

An object of the present invention is to solve such a conventional problem and to obtain the same effect as mounting these electric parts without separately mounting a resistor or a capacitor on a circuit in a flexible substrate. To provide a pattern.

[0011]

Means and Actions to be Solved by the Invention The constitution for achieving the object of the present invention is as described in the claims, and specifically, the shape of the copper foil pattern formed on the flexible substrate is as follows. Have the following characteristics.

1) A copper foil pattern having a large area is formed only in a part in the vicinity of an electric component in a power supply line and a GND line of an important electric component which is not desired to malfunction.

2) In the copper foil pattern of the control signal line in which external noise (power line noise, electrostatic noise, etc.) is not desired to be superimposed, the copper foil pattern portion having a small area, as described in 1). Alternately form large copper foil patterns.

By forming the pattern as in 1), a capacitor using polyimide resin as a dielectric is formed between the power supply line and the GND line, which is a conventional technique. It is possible to give an action equivalent to that when a capacitor is mounted between lines.

Further, by forming a copper foil pattern as in 2), a polyimide resin is used as a dielectric between the control signal line and the power supply line or the GND line in the copper foil pattern portion having a large area. A conventional capacitor is formed, and the control signal line and the power supply line or the control signal line and the GND which are the conventional techniques are formed.
It is possible to give an action equivalent to that when a capacitor is mounted between lines.

Further, by forming a copper foil pattern portion having a small area, the resistance component can be made higher than that of other portions, so that a resistance higher than that of a normal copper foil pattern is provided. It becomes possible.

Therefore, by alternately arranging a large area copper foil pattern portion and a small area copper foil pattern portion on the control signal line where external noise is not desired to be superimposed, capacitors and resistors are alternately arranged. It is possible to provide an operation equivalent to what is done, that is, an operation equivalent to configuring a noise filter which is a conventional technique.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention.
Reference numeral 1 is a power line pattern, 102 and 104 are control signal line patterns, and 103 is a GND line pattern. In addition, a broken line circle in the GND line pattern 103 indicates a counter electrode layer made of copper paste, which will be described later, and a G
The position for conducting the ND line pattern is shown.

FIG. 3 shows the structure of the flexible substrate. Three
Reference numeral 01 is a solder surface cover film, which uses an insulating material such as a polyimide material. A base film 302 is made of an insulating material such as a polyimide material, like the solder side cover film 301. Between the solder surface cover film 301 and the base film 302, a counter electrode layer is formed by vapor-depositing or printing a copper paste electrically connected to the GND line pattern for the purpose of preventing external noise. Reference numeral 303 denotes a component side cover film, which is made of an insulating material such as a polyimide material like the solder side cover film 301 and the base film 302. A copper foil pattern (FIG. 1) is formed between the base film 302 and the component surface cover film 303. Reference numeral 304 denotes a circuit element, for example, an electric component such as a photo sensor IC that is weak against noise.

In FIG. 1, a power line pattern 10 is provided.
The shaded portion 106 of No. 1 is provided in the vicinity of an important electric component which is not desired to be malfunctioned, has a counter electrode layer made of the copper paste described in FIG. It is a copper foil pattern portion for forming a capacitor as a derivative.

On the other hand, the control signal line pattern 102.
In the figure, reference numerals 105a to 105g denote copper foil pattern portions (hereinafter referred to as capacitance components) having a large area for giving a large capacitance component on the control signal line. Further, the copper foil pattern between the capacitance components 105a and 105b is a copper foil pattern having a small area for the purpose of increasing the resistance component.

In the above-mentioned structure, the external noise superimposed on the power supply line or the GND line is generated at the portion forming the capacitor between the shaded portion 106 of the copper foil pattern 101 for the power supply line and the counter electrode. Attenuated (noise removed).

The external noise superimposed on the control signal line is the resistance of the copper foil pattern up to the capacitance component 105g, the capacitance components 105g, the resistance of the copper foil pattern between 105g and 105f, the capacitance component 105f, ... , 105b and 105a, passing through the resistance and capacitance components 105a of the copper foil pattern can be regarded as equivalent to passing through a circuit having an equivalent circuit of the distributed constant circuit as shown in FIG. Therefore, the external noise superposed on the control signal line is contaminated by the capacitors (203a, ..., 203).
g), noise filters (201a, 201b, 201a ', 20) composed of resistors (202a, ..., 202g)
Since 1b 'corresponds to passing through the terminal), it is sufficiently attenuated before reaching the circuit element 304.

4 and 5 show a second embodiment of the present invention.

Although the above embodiment has been described by using the copper paste for the single-sided flexible substrate, this embodiment can use the double-sided flexible substrate to provide the same operation and effect.

In FIG. 4, reference numerals 402 and 404 are control signal line patterns.

FIG. 5 shows the structure of the double-sided flexible substrate. 501 is a component side cover film and uses an insulating material such as a polyimide material. 502 is an A base film, and like the component side cover film 501,
An insulating material such as polyimide is used. Between the component side cover film 501 and the A base film 502,
A power line pattern is arranged. 503 is a B base film, and the component side cover film 501,
Like the A base film 502, it is made of an insulating material such as a polyimide material. Reference numeral 504 denotes a solder side cover film, which is made of an insulating material such as a polyimide material like the component side cover film 501, the A base film 502, and the B base film 503.

A control signal line copper foil pattern (FIG. 4) is formed between the A base film 502 and the B base film 503. A copper foil pattern for the GND line is formed between the B base film 503 and the solder side cover film 504.

In this case, the power supply line copper foil pattern formed between the films 501 and 502 and the film 5
Therefore, the copper foil pattern for the GND line formed between 03 and 504 has different polarities, and the A base film made of a polyimide material is used as a dielectric to form a capacitor.

In the control signal line between the A base film 502 and the B base film 503, again, a copper foil pattern having a large area for giving a capacitance component and a copper foil having a small area for giving a resistance component are provided. Alternate the foil patterns.

With this structure, it is possible to obtain the same effect as that of the first embodiment.

[0032]

EFFECTS OF THE INVENTION It is possible to supply a stable power supply to electric parts by substituting these functions with only a flexible substrate without mounting elements such as a condenser and a resistor.

Further, the level of the control signal line can be transmitted at a constant level with respect to the power supply or GND so that an external noise or the like will not be superimposed on the control signal line to prevent malfunction.

Since only a flexible substrate can be used, even if the substrate has an extremely small size,
It is possible to give the same effect as the above.

[Brief description of drawings]

FIG. 1 is a plan view of a wiring pattern of a flexible substrate showing a first embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram of the flexible substrate shown in FIG.

3 is an exploded perspective view of the flexible substrate shown in FIG.

FIG. 4 is a plan view of a wiring pattern of a flexible substrate showing a second embodiment.

5 is an exploded perspective view of the flexible substrate shown in FIG.

[Explanation of symbols]

 101 ... Power supply line pattern 102, 104 ... Control signal line pattern 103 ... GND line pattern 105, 106 ... Capacitive component pattern

Claims (4)

[Claims] 1. In a flexible substrate using an insulating film such as a polyimide film as a substrate material of an electric circuit substrate, the shape of a copper foil pattern in a circuit pattern is compared only partially with other pattern portions of the copper foil pattern. To form a large surface area copper foil pattern for counter electrodes,
A surface area equal to or larger than that of the counter electrode copper foil pattern portion is provided on a part of the copper foil pattern for power supply or the copper foil pattern for GND facing the copper foil pattern portion having the large surface area with the insulating film sandwiched therebetween. Forming a copper foil pattern portion having the same, using the insulating film as a dielectric, and providing a large capacitance component in the copper foil pattern for power supply and the copper foil pattern for GND as compared with a normal copper foil pattern portion. A circuit pattern on a flexible substrate. 2. In the circuit pattern of the flexible substrate,
A copper foil pattern for a counter electrode having a large surface area is formed, and a part of the copper foil pattern for a power source facing the copper foil pattern for a counter electrode has a surface area equal to or larger than that of the counter electrode copper foil pattern. Forming a partial large-area copper foil pattern portion having, using an insulating film such as a polyimide film as a dielectric, the counter electrode copper foil pattern and the power source partial large-area copper foil pattern portion, and a normal copper foil pattern By comparison, a circuit pattern on a flexible substrate that has a large capacitance component. 3. In the circuit pattern of the flexible substrate,
A copper foil pattern having a large surface area is formed, and a copper foil pattern for GND is formed at a portion opposite to the copper foil pattern having a surface area equal to or larger than that of the copper foil pattern having a large surface area. A circuit pattern characterized in that a film is used as a dielectric, and a copper foil pattern having a large surface area and a copper foil pattern for GND have a large capacitance component as compared with a normal copper foil pattern. 4. The copper foil pattern portion having a large capacitance component and the copper foil pattern portion having an extremely small surface area are alternately formed in the same pattern according to claim 2 or 3. Circuit pattern to do.