CN201234406Y

CN201234406Y - Flexible printed circuit board

Info

Publication number: CN201234406Y
Application number: CNU2008201266394U
Authority: CN
Inventors: 孙仕红; 彭小宁
Original assignee: BYD Co Ltd
Current assignee: Shenzhen Holitech Optoelectronics Co Ltd
Priority date: 2008-06-27
Filing date: 2008-06-27
Publication date: 2009-05-06
Anticipated expiration: 2018-06-27

Abstract

The utility model discloses a flexible printed circuit (FPC), which comprises a gold finger pad consisting of two independent single-sided pads, wherein the two single-sided pads are the same in shape and electrical performance and are respectively arranged on the front and the back surfaces of the FPC in the corresponding mirror image positions, to form the double-sided pad; and a through hole formed at the upper end of each of the two single-sided pads, wherein wires are led out of the two single-sided pads and connected with the through hole. The wires are led out of the two surfaces of the gold finger pad and communicated with the wires in the upper-end element region. Therefore, if the pad on one surface is broken or stripped, the wires on the other surface are still connected with the wires in the upper-end element region, thereby greatly improving the conduction between the double-sided pad and the upper-end element region and improving the reliability of the FPC. Furthermore, the two surfaces of the gold finger pad are communicated through the through hole at the upper end, thereby improving the conductivity of the gold finger pad.

Description

A kind of flexible printed wiring board

Technical field

The utility model relates to the flexible printed wiring board technology, refers to a kind of flexible printed wiring board with the two-sided pad of enhancement mode especially.

Background technology

Along with developing rapidly of electron trade, the application of flexible printed wiring board (FPC, Flexible PrintedCircuit) in electronic product is more and more wider, all can use in nearly all consumer electronic product.FPC is general, and all the realization electric function links together with common printed substrate (PCB, Printed Circuit Board).

Fig. 1 is the structural representation of a kind of FPC in the prior art, as shown in Figure 1, this FPC by two surface insulation layers 1, insulated substrate 2 and lay respectively at insulated substrate 2 and two surface insulation layers 1 between two copper foil layers 3 form, copper foil layer 3 lower ends of both sides form the golden finger pad 4 of both sides through corrosion, and the surface insulation layer 1 of both sides cuts out certain-length and forms and window so that the golden finger pad 4 of both sides exposes in the space to the outside.Among the FPC shown in Figure 1, golden finger pad 4 is two-sided pad, in PowerLogic two-sided pad as one independently element encapsulate.The equal in length of windowing of both side surface insulating barrier 1, the equal in length of windowing of the length of the golden finger pad 4 of both sides and the surface insulation layer 1 in the outside.

At present, being connected between FPC and the PCB, mainly adopt scolding tin to connect or anisotropic conductive film (ACF, Anisotropic Conductive Film) hot pressing connects two kinds of methods.

Wherein, the scolding tin method of attachment is simple, cost is low.Because the conductive pin contact area of FPC and PCB is bigger, and conducting resistance is smaller, adopt artificial welding or hot pressing welding equipment operate all can, adopt the FPC of scolding tin connection repeatedly to reprocess.Usually, the PCB of conductive pin spacing Pitch more than 0.7mm adopts the scolding tin method to connect.Failure welding problem common in the scolding tin method of attachment has: connect that tin short circuit, bump excessive height, rosin joint, two-sided pad come off, the pad fracture causes and open circuit etc.If two-sided pad connectedness is bad, the function of whole module all can be affected even interrupt.

Fig. 2 a is the schematic diagram of golden finger pad in FPC, and Fig. 2 b is the partial structurtes enlarged diagram of golden finger pad among Fig. 2 a.From Fig. 2 b as seen, at present, in the two-sided pad of FPC, in order to increase the connectedness of two-sided pad upper and lower surface, can add in the middle of two-sided pad and leak tin circular hole 21, perhaps add in the pad bottom and leak tin semicircle orifice 22, leaking tin circular hole 21 or leaking tin semicircle orifice 22 all is the via that makes two-sided connection.Since two-sided pad as one independently element encapsulate, existing two-sided pad can only have a pad to draw cabling to be connected with the element area 23 of the upper end that is used to arrange components and parts, if draw the pad fracture or the fracture of cabling place of cabling, so, the connectedness of the circuit of two-sided pad and upper end element area 23 is interrupted probably, thereby causes the connection of FPC unreliable.

Summary of the invention

In view of this, main purpose of the present utility model is to provide a kind of flexible printed wiring board, can strengthen the reliability of FPC.

For achieving the above object, the technical solution of the utility model specifically is achieved in that

A kind of flexible printed wiring board FPC, in described FPC,

The golden finger pad is made up of two independences and the shape single face pad identical with electric property;

Two single face pads are separately positioned on the mirror position of tow sides correspondence of FPC;

Two single face pads are drawn cabling respectively, and described cabling is connected with a via hole that is provided with two single face pad upper ends respectively.

As seen from the above technical solution, golden finger pad among the utility model FPC by two independently the single face pad form, the shape and the electric property of two single face pads are identical, are separately positioned on the mirror position of tow sides correspondence of FPC, to form two-sided pad; Two single face pads are drawn cabling respectively, and described cabling is connected with a via hole that is provided with two single face pad upper ends respectively.

The two sides of golden finger pad all can be drawn cabling and is communicated with the circuit of upper end element area, if wherein pad fracture or come off, still can be connected with the circuit of upper end element area by the cabling of another side, increase the connectedness of two-sided pad and upper end element area greatly, thereby strengthened the reliability of FPC.And the two sides of golden finger pad is communicated with by the via hole of upper end, has also increased the connectedness of golden finger pad itself.

Description of drawings

Fig. 1 is the structural representation of a kind of FPC in the prior art;

Fig. 2 a is the position view of prior art golden finger pad in FPC;

Fig. 2 b is the partial structurtes enlarged diagram of golden finger pad among Fig. 2 a;

Fig. 3 is the position view of golden finger pad in FPC of the utility model one preferred embodiment;

Fig. 4 a is the structural representation in the front of golden finger pad in FPC of the utility model one preferred embodiment;

Fig. 4 b is the structural representation at the back side of golden finger pad in FPC of the utility model one preferred embodiment.

Embodiment

For making the purpose of this utility model, technical scheme and advantage clearer, below with reference to the accompanying drawing embodiment that develops simultaneously, the utility model is further described.

Among the FPC of the present utility model, the golden finger pad by two independently the single face pad form, be provided with a via hole in the upper end of two single face pads, two single face pads are drawn cabling respectively and are connected with this via hole.Specifically, the element of two-sided pad among the PowerLogic is copied into two elements, and duplicate the component package that obtains with these two respectively and become two independently forms of single face pad, like this, correspond among the PowerPCB, these two independently single welding disk shape such as size dimension and electric property are identical.Two independently the single face pad to be separately positioned on the position of tow sides correspondence of FPC be on the mirror position, to form two-sided pad.Be provided with a via hole in the upper end of two single face pads, two single face pads are drawn cabling respectively and are connected with this via hole.

The size of the size of via hole and other via hole of whole FPC can be identical, the single face pad to the trace width of via hole can with pad on the via hole with wide or be narrower than the width of the pad of via hole.

Fig. 3 is the position view of the utility model golden finger pad in FPC, wherein only illustrates the one side of FPC, as cabling 42 one side only is shown.Below in conjunction with Fig. 4 a and Fig. 4 b golden finger pad of the present utility model is done detailed description.

Fig. 4 a is the structural representation in the front of the utility model golden finger pad in FPC, and Fig. 4 b is the structural representation at the back side of utility model golden finger pad in FPC.With the golden finger pad in the frame of broken lines is that example describes, suppose to be among Fig. 4 a pad a, among Fig. 4 b pad b, so, pad a and pad b are two independently single face pads, and shape and the electric property of pad a and pad b are identical, shown in Fig. 4 a and Fig. 4 b, pad a and pad b are separately positioned on the double-edged mirror position of FPC, to form the golden finger pad.Punch to form via hole 41 in the upper end of pad a and pad b; Pad a draws cabling 42a respectively with pad b and links to each other with via hole 41 with cabling 42b.From golden finger pad of the present utility model as can be seen, the two sides of golden finger pad all can be drawn cabling by via hole 41 separately and is communicated with the circuit of upper end element area, if wherein pad fracture or come off, still can be connected with the circuit of upper end element area by the cabling of another side, increase the connectedness of two-sided pad and upper end element area so greatly, thereby strengthened the reliability of FPC.And the two sides of golden finger pad is communicated with by the via hole of upper end, has also increased the connectedness of golden finger pad itself.

In addition, in order to increase the double-edged connectedness of golden finger pad, shown in Fig. 3 a and Fig. 3 b, Lou tin circular hole 43 can be set in the centre of pad a and pad b, and/or Lou tin semicircle orifice 44 is set at pad a and pad b bottom, leaking tin circular hole 43 and leaking tin semicircle orifice 44 all is the via that is communicated with up and down.

Further, in order to reduce the possibility that the golden finger pad comes off, in conjunction with Fig. 1, can make the golden finger pad promptly be positioned at double-edged two independently the length of single face pad all greater than the length of windowing of surface insulation layer.In order to reduce the possibility that pad fractures, the length that the golden finger pad that the length of windowing of two surface insulation layers promptly exposes in two single face pads can also further be set is inconsistent, difference is 0.3 millimeter (mm)～0.5mm, such as the length of a single face pad wherein is 2.5mm, and the length of another side single face pad is 2.2mm.

The above is preferred embodiment of the present utility model only, is not to be used to limit protection range of the present utility model.All within spirit of the present utility model and principle, any modification of being done, be equal to and replace and improvement etc., all should be included within the protection range of the present utility model.

Claims

1. a flexible printed wiring board FPC is characterized in that, in described FPC,

2. flexible printed wiring board according to claim 1 is characterized in that, Lou tin circular hole is set in the centre of described single face pad, and/or at the described single welding end of trying to get to the heart of a matter Lou tin semicircle orifice is set; Described leakage tin circular hole and leakage tin semicircle orifice all are vias that described two single face pads are communicated with.

3. flexible printed wiring board according to claim 1 and 2 is characterized in that, the width of described cabling and the pad of via hole are with wide or be narrower than the width of the pad of via hole.

4. flexible printed wiring board according to claim 1 and 2 is characterized in that, described two independently the length of single face pad all greater than the length of windowing of the surface insulation layer among the described FPC.

5. flexible printed wiring board according to claim 4 is characterized in that, the difference of windowing between the length of described two surface insulation layers is 0.3 millimeter～0.5 millimeter.

6. flexible printed wiring board according to claim 4 is characterized in that, the length of a single face pad in described two single face pads is 2.5 millimeters, and the length of another side single face pad is 2.2 millimeters.