CN1725931B

CN1725931B - Flexible printing substrate

Info

Publication number: CN1725931B
Application number: CN2005100814015A
Authority: CN
Inventors: 上田信吾
Original assignee: Sumitomo Electric Printed Circuits Inc
Current assignee: Sumitomo Electric Printed Circuits Inc
Priority date: 2004-07-06
Filing date: 2005-06-30
Publication date: 2011-05-11
Anticipated expiration: 2025-06-30
Also published as: JP4398311B2; TW200614884A; KR101098132B1; JP2006024584A; TWI368464B; KR20060048487A; CN1725931A

Abstract

The present invention provides a flexible printed board having a conductor portion for interconnecting circuit members and produced by laying a plurality of substrates in layers in which frictional sound is not generated at the time of bending even if releasable resin is not applied to the contact surface between the substrates.In the flexible printed board, protrusions and recesses are provided on the contacting side surface of the substrate especially by polishing or embossing.

Description

Flexible printed board

Technical field

The present invention relates to the flexible printed board of a kind of hinge that is used for collapsible mobile phone etc.

Background technology

In collapsible mobile phone or collapsible PC etc., by can rotary axis of earth propping up in the electronic equipment that two lids on hinge constitute, for being electrically connected, use the pliability flexible printed board that on basal film, has wire portion with being located at two circuit blocks on the lid respectively.This flexible printed board is big repeatedly degree of curvature with the folding-type electronic device folding.

Therefore, for minimizing follow crooked produced stress, for example, as shown in Figure 1, helical coil was provided with around one week of rotating shaft of hinge.In addition, the connecting portion among Fig. 1 (and Fig. 2 described later, 3) is with the wire portion of flexible printed board and the part of circuit block electrical connection.

But, even according to such method to set up, because between interior all sides of reeling and outer circumferential side, the extension when crooked varies in size, and is easy to generate stress in the substrate.Therefore, motion have with interior all sides and outer circumferential side be separated into two substrates, these two substrates are overlapped and flexible printed board.

For example, disclose in No. 3515490 communique of Japan Patent with substrate shown in Figure 2 along the broken curve doubling, as shown in Figure 3 two substrates are overlapped and flexible printed board (Fig. 1, Fig. 2 of No. 3515490 communique of Japan Patent).Like this, by forming by with interior all sides and the outer circumferential side substrate that constitutes of film independently,, also can disperse crooked stress even during the folding-type electronic device folding.

In addition, the spy opens and also discloses the flexible printed board that two substrates coincidences are got in the 2004-79730 communique (claim 1).In this flexible printed board, the film otch with a substrate is bent it easily.

But, such flexible printed board that a plurality of substrates are overlapped, when it is crooked, phase mutual friction between the face that the substrate of coincidence is in contact with one another and produce fricative.Therefore, for addressing this problem, implement on the surface of film coating silicon at present and be the countermeasures such as resin that resin etc. has release property.

But flexible printed board has the part island shape portion etc. for example that is used for installing component usually, in addition, is stained with stiffener by bonding agent.Part such as this island shape window and the position that is stained with stiffener must be avoided being coated with and apply the resin with release property.Therefore, must avoid the resin that these part coatings have release property, the result, the operability of coating is very low.

In addition, even avoid the resin that these part coatings have release property, also have resin and be exuded to island shape window and the part that adheres to stiffener from coated part, the result also becomes the reason that causes bonding bad grade.Therefore, expectation does not apply resin with release property and does not have fricative flexible printed board when crooked.

No. 3515490 communique of patent documentation 1 Japan Patent

Summary of the invention

The invention provides and a kind ofly have the wire portion that is used for to connect between circuit block, overlap the flexible printed board that a plurality of substrates form, between substrate even the face that is not in contact with one another coating has the resin of release property, the fricative when also not bending.The present inventor finds that frictional force is more little after having studied the frictional force on basal film surface of substrate and fricative relation, and fricative is more little, and, for the contact area that reduces between the substrate that this frictional force reduces mutual rubbing surface side is effective; For reducing this contact area, setting up concavo-convex on the basal film surface of substrate is effectively, thereby has finished the present invention.

The invention provides a kind of flexible printed board, it has the wire portion that is used for connecting between circuit block, forms by a plurality of substrates are overlapped, and it is characterized in that, set up concavo-convexly at the substrate surface that is in contact with one another a side, the concavo-convex size of substrate surface is 0.5～6.0 μ m.

This flexible printed board is made of pliability basal film and the single or double on being located at this basal film and the wire portion in the basal film usually.Wire portion is used for being electrically connected being located at respectively between two circuit blocks on the lid, and these two lids can rotate the earth's axis by hinge and prop up.Basal film is suitable for thermal endurance and the good polyimide resin of mechanical strength.

The coincidence of two substrates such as Fig. 2, shown in Figure 3 can be the methods along the broken curve doubling, also can be additive methods.In addition, broken curve also is not limited to line in the example of Fig. 2, Fig. 3, parallel with the length direction of flexible printed board.For example, can be the method for the edge line doubling vertical with length direction.

The scope of concavo-convex big or small preferred 0.5～6.0 μ m.Concavo-convex size is if surpass 6.0 μ m, and then the slip variation between substrate can produce on the contrary and rub the fricative that pulls, or the bendability variation.And concavo-convex size prevents that fricative effect is insufficient during less than 0.5 μ m.The corresponding the preferred embodiment of the flexible printed board of second aspect present invention, in this flexible printed board, the concavo-convex size of substrate surface is 0.5～6.0 μ m.Can prevent fricative by setting up concavo-convex, and, connecting airtight that power can not reduce and instead improve when adhering to stiffener etc. by bonding agent.

The substrate surface that is in contact with one another a side is set up concavo-convex method, for example by the method for lapped faces such as grinding agent.The flexible printed board that third aspect present invention provides is to should embodiment, and in this flexible printed board, the concavo-convex of substrate surface forms by the method for grinding substrate surface.

The for example minimum aluminium oxide of employed grinding agent, silica, chemical fibre etc.In addition, grinding can use such device to carry out: sandblast, be about to minimum aluminium oxide, silicon oxide particle etc. with blast bump against aforesaid substrate surface such by the device on the grinding-material; Wet shot (ウェ Star ト Block ラスト), be about to minimum aluminium oxide, silicon oxide particle etc. and infiltrate in the water, bump against by the device on the grinding-material with hydraulic pressure; Brush grinding (Block ラシ grinding), be in the roller brush rotation of chemical fibre by by grinding-material, form concavo-convex device on the surface; Or the like.

Set up the embossing method for processing that concavo-convex method is for example utilized the surface as other at substrate surface.The flexible printed board that fourth aspect present invention provides is equivalent to this embodiment, and in above-mentioned flexible printed board, the concavo-convex of substrate surface is processed to form by embossing.

At this, embossing processing is to be that concavo-convex processing is set up on the surface of machined material on the surface, and for example, the concavo-convex metallic roll that has after utilization will be heated contacts with film, sets up concavo-convex method at film surface and carries out.Heating-up temperature is high, and processability is good, but too high, and the surface causes change in size or coking owing to heat is out of shape, so heating-up temperature is 150～250 ℃ of degree usually.

Grind and embossing process can be before flexible printed board forms basal film and coverlay (coverlay film; カバ one レイ Off イ Le ㄙ) carries out on the polyimide film that uses in.In addition, sandblast, wet shot, brush grinding also can be carried out at basal film and on the film after covering processing.In addition like this, after applying grinding or embossing processing on the basal film, can form wire portion at the reverse side of basal film.Such processing is easy, follows these process for producing can not descend.

Fricative even do not have the resin of release property in the substrate surface coating that is in contact with one another a side, does not take place between substrate surface when crooked in flexible printed board of the present invention yet.Owing to there is no need to apply resin, there is no need to adopt the local low manufacture method of the coating such operability of processing of implementing with release property.In addition, formerly the problem of technology is promptly oozed out to island shape window etc. and is not existed, and follows the bad grade of adhesion of this problem also not take place.And then, concavo-convex by setting up on the surface, thus the frictional force between substrate surface reduces, the mutual degree of freedom of the substrate when hinge is crooked increases, and stress disperses, so bendability (compliance) improves.

Description of drawings

Fig. 1 is the plane graph that one of expression flexible printed board makes use-case;

Fig. 2 is the plane graph of example of a process of the manufacturing of expression flexible printed board;

Fig. 3 is the plane graph of an example of expression flexible printed board.

Embodiment

Illustrate according to embodiment below and implement optimal way of the present invention.In addition, the invention is not restricted to this mode, only otherwise damage purport of the present invention, can be altered to other modes.

(embodiment)

Embodiment 1

The aluminium oxide that uses #800 forms height and digs the concavo-convex of dark 2 μ m with the single face that 10～30mm/ grinds polyimide resin (カプト Application HA, thickness 25 μ m) film second.Make substrate shown in Figure 2 with this polyimide resin film.In addition, the length of substrate (interval between connecting portion) is 55mm, and the width of substrate is 8mm.

Wire portion is formed by etching behind the long-pending Copper Foil of the surface layer opposite with the face that ground, and lamination polyimides (カプト Application HA, thickness 25 μ m) film is a coverlay thereon.The substrate of gained along the doubling of Fig. 2 broken curve, is obtained flexible printed board shown in Figure 3.This substrate is wound on as shown in Figure 1 on the hinge of collapsible mobile phone, connects the interior circuit block of each lid of collapsible mobile phone.

Behind the coiling, carry out the folding of collapsible mobile phone, confirm that by the method that ear is listened evaluation has or not fricative, it the results are shown in table 1.In addition, the collapsible mobile phone of folding is measured the number of times that produces broken string up to wire portion repeatedly, estimates bendability.It the results are shown in table 1.

Embodiment 2

Replace and grind, under following condition, except that the embossing processing that utilizes heat lamination (Hot ラミ) to carry out, similarly to Example 1, on the single face of polyimide resin, form height and dig the concavo-convex of dark 2 μ m, make flexible printed board.Afterwards, identical with embodiment 1, estimate fricative and have or not and bendability.It the results are shown in table 1.

Embossing processing conditions: will set up the concavo-convex metallic roll of 2 μ m and be heated to 190 ℃, and make film divide to flow to therebetween and process with 10mm/.

Comparative example

Do not form concavo-convex outside, identical with embodiment 1, produce flexible printed board.Then, similarly to Example 1, estimate fricative and have or not and bendability.The results are shown in table 1.

Table 1

?	Processing method	Surface roughness (concavo-convex)	Have or not fricative	Bendability
					Embodiment 1	Surface grinding	2μm?	Do not have	320,000 times
Embodiment 2	Embossing processing	2μm?	Do not have	300,000 times
					Comparative example	Do not have	-?	Have	140,000 times

As shown in Table 1, do not form the flexible printed board of concavo-convex comparative example and produce fricative when crooked, and flexible printed board of the present invention does not produce fricative.In addition, bendability and comparative example are equal to above.

Claims

1. flexible printed board, it has the wire portion that is used for connecting between circuit block, and a plurality of substrates are overlapped and form, and sets up concavo-convexly at the substrate surface that is in contact with one another a side, it is characterized in that the concavo-convex size of substrate surface is 0.5～6.0 μ m.

2. flexible printed board as claimed in claim 1 is characterized in that, the concavo-convex of substrate surface forms by the method for grinding substrate surface.

3. flexible printed board as claimed in claim 1 is characterized in that, the concavo-convex of substrate surface forms by substrate surface being carried out the embossing method for processing.