CN101546622A

CN101546622A - Soft arranging wire with adjustable impedance

Info

Publication number: CN101546622A
Application number: CN200810300723A
Authority: CN
Inventors: 郑永昌
Original assignee: Foxconn Kunshan Computer Connector Co Ltd; Hon Hai Precision Industry Co Ltd
Current assignee: Foxconn Kunshan Computer Connector Co Ltd; Hon Hai Precision Industry Co Ltd
Priority date: 2008-03-26
Filing date: 2008-03-26
Publication date: 2009-09-30

Abstract

The invention relates to a soft arranging wire with adjustable impedance, which comprises an insulating layer of a first layer, a conducting wire layer of a second layer, an insulating layer of a third layer, a medium layer of a forth layer and a metal shielding layer of a fifth layer, wherein the conducting wire layer of the second layer is provided with a plurality of conductive wires which are coated between the insulating layer of the first layer and the insulating layer of the third layer. Compared with the prior art, the soft arranging wire with the adjustable impedance can achieve the aim of adjusting the characteristic impedance of the soft arranging wire by selecting medium materials with different dielectric constants and adjusting the thickness of the medium materials because of increasing the medium layer of the forth layer and the metal shielding layer of the fifth layer.

Description

The soft arranging wire of adjustable impedance

[technical field]

The present invention relates to a kind of FFC (flexible flat cable) that is used to connect LCD (LCD) and system host board, especially refer to a kind of FFC of adjustable impedance.

[background technology]

Please refer to Fig. 1, employed signal transmission interface between present LCD and the system host board, adopt tool ultrahigh speed 1.4Gb/s, low-power, and the Low Voltage Differential Signal receiver of low electromagnetic characteristic (Low Voltage Differential Signal LVDS) is signal transmission interface.

Therefore, LVDS interface standard according to the ANSI/TIA/EIA-644-1995 definition, be applied to the LVDS signal transmssion line specification between LCD interface and the system host interface, must possess 100 Ω characteristic impedances, could mate with the circuit impedance of LCD interface and system host plate interface.

In other words, be applicable to the signal transmssion line between LCD interface and the system host plate interface, traditional connecting line, flexible printed wiring board (the Flexible Printed Circuit that must possess the characteristic impedance of 100 Ω, FPC) or mini coaxial cable (MiniCoaxial Cable) etc., could the instruction of correct execution transmission signals, reduce electromagnetic interference, reduce noise jamming and avoid malfunction, as not so, will produce signal reflex and noise jamming, thereby cause the loss of signal, distortion and distortion.

The characteristic impedance value of general flexible flat cable approximately all about 130 Ω, does not meet the use specification standards of LVDS signal transmssion line, is not suitable for as the LVDS signal transmssion line between LCD interface and the system host plate interface.Yet flexible flat cable simple in structure is generally by last layer insulating, electric wire layer and layer insulating is superimposed down constitutes three layer laminate structures; Should go up layer insulating and reach the material of layer insulating down, go up special saturated polyester resin and make by PET (polyethylene terephthalate) film coating, the hot pressing of process machine is coated on the electric wire layer middle and constitutes one, so, have advantage simple for production and cheap for manufacturing cost, and have softness, anti-combustion, cold-resistant thermal property again.

If can and accurately be limited in about 100 Ω with the characteristic impedance adjustment of flexible flat cable, just can satisfy the use specification requirement of LVDS signal transmssion line, except the manufacturing cost that can save the LVDS signal transmssion line in a large number, also can reform and develop the new purposes of flexible flat cable; Make flexible flat cable can be used as LVDS signal transmssion line purposes and use, and make the LVDS signal transmssion line have the softness characteristics of flexible flat cable.

Chinese patent is announced CN1278338C number and has been disclosed the FFC that a kind of characteristic impedance can be controlled in 85-115 Ω, and it constitutes laminated construction by first insulating barrier, second layer electric wire layer, three-layer insulated layer and the 4th layer of metal screen layer are superimposed.Wherein, metal screen layer has many identical shaped hollow-out unit.

Yet, though above-mentioned four-layer structure FFC can control characteristic impedance at 85-115 Ω, the hollow-out unit of metal screen layer is comparatively complicated in industrial process, is unfavorable for suitability for industrialized production.

Therefore, be necessary such FFC is improved, to address the aforementioned drawbacks.

[summary of the invention]

The object of the present invention is to provide a kind of soft arranging wire of adjustable impedance.

To achieve these goals, the soft arranging wire of adjustable impedance of the present invention is reached in the following manner:

A kind of soft arranging wire of adjustable impedance, it comprises: ground floor insulating barrier, second layer electric wire layer and three-layer insulated layer, described second layer electric wire layer has some electric wires, is covered by between first insulating barrier and the 3rd insulating barrier; It is characterized in that: this soft arranging wire also comprises the 4th layer of dielectric layer and layer 5 metal shielding layer.

Than prior art, the soft arranging wire of adjustable impedance of the present invention has following beneficial effect:

The soft arranging wire of adjustable impedance of the present invention can reach the purpose of the characteristic impedance of regulating soft arranging wire by the dielectric material of selecting differing dielectric constant and the thickness of regulating dielectric material because of having increased the 4th layer of dielectric layer and layer 5 metal shielding layer.

[description of drawings]

Fig. 1 is with the schematic diagram of LVDS signal place coffret as the signal transmission between LCD interface and the system host plate interface.

Fig. 2 is the soft arranging wire cut-away view of adjustable impedance of the present invention.

Fig. 3 is the schematic diagram that the soft arranging wire of adjustable impedance of the present invention connects LCD interface and system host plate interface transmission LVDS signal.

[embodiment]

It is shown in Figure 2 to please refer to figure, and the FFC40 of adjustable impedance shown in the present comprises ground floor insulating barrier 41, second layer

electric wire layer

42,43, the 4th layers of dielectric layer 44 of three-layer insulated layer and layer 5 metal shielding layer 45.FFC40 is used for connecting LCD and motherboard by electric connector, thus transmission LVDS signal.

Wherein, second layer electric wire layer 42 has some the tin-coated copper electric wires to be arranged side by side at interval, can be used to transmission signals.And ground floor insulating barrier 41 and three-layer insulated layer 43, being coated with special saturated polyester resin with the PET film is material, second layer electric wire layer 42 is coated on middle, except the tin-coated copper electric wire two ends that make second layer electric wire layer 42 expose outside, remainder is all coated by ground floor insulating barrier 41 and three-layer insulated layer 43, and and external insulation.

On the three-layer insulated layer 43, paste one deck dielectric layer 44 again, this layer dielectric layer 44 can be PET or other plastic materials.Because of different media has different dielectric constants, and the thin and thick of dielectric layer also can influence the impedance of this dielectric layer.Different applied environments may need the FFC of different-thickness, therefore, can select different materials as dielectric layer 44, thereby is suitable for the impedance matching of specific thicknesses FFC.

At the 4th layer above the dielectric layer 44, paste layer of metal layer shielding layer 45 again.This metal shielding layer 45 can be any of metal such as Copper Foil, aluminium foil, free silver slurry, silver-colored carbon slurry, silver foil and metallic composite kind.This layer 5 metal shielding layer 45 can be used as the ground connection of FFC 40, can make FFC 40 have better conductibility.Certainly, the grounded parts of the electric connector that this layer 5 metal shielding layer 45 also can be connected with FFC 40 electrically connects, thereby makes the ground connection better effects if of the combination of this FFC 40 and electric connector.

The FFC 40 of adjustable impedance of the present invention regulates impedance by the thickness of dielectric layer 44 is different with the dielectric constant of different medium material, thereby the characteristic impedance of FFC 40 and electric connector are complementary.For example, under certain conditions, dielectric layer 44 need or only have this kind plastic material with a kind of specific plastic material, then can make FFC 40 reach impedance matching by the thickness of regulating dielectric layer.Again for example, under certain conditions, FFC requires specific thickness, then can be by selecting different dielectric materials as dielectric layer, and satisfy FFC and promptly satisfy specific thicknesses and can reach impedance matching again.

The FFC 40 of adjustable impedance of the present invention is not limited to transmission LVDS signal, because the characteristic impedance of the FFC40 of adjustable impedance of the present invention can be done adjusting to the characteristic impedance of FFC 40 by the material selection and the thickness adjusted of dielectric layer, so, be not can use under other environment of 100 Ω needing characteristic impedance for FFC40 yet.The FFC 40 of adjustable impedance of the present invention can reach by the processing procedure and the lower-cost material of more convenient suitability for industrialized production, is very beneficial for suitability for industrialized production and reduces the cost of FFC when being applied to LVDS.

Claims

The soft arranging wire of [claim 1] a kind of adjustable impedance, it comprises: ground floor insulating barrier, second layer electric wire layer and three-layer insulated layer, described second layer electric wire layer has some electric wires, is covered by between first insulating barrier and the 3rd insulating barrier; It is characterized in that: this soft arranging wire also comprises the 4th layer of dielectric layer and layer 5 metal shielding layer.
The soft arranging wire of [claim 2] adjustable impedance as claimed in claim 1 is characterized in that: the 4th layer of dielectric layer is covered on the above the three-layer insulated layer, and this layer dielectric layer can be PET or other plastic materials.
The soft arranging wire of [claim 3] adjustable impedance as claimed in claim 1, it is characterized in that: described layer 5 metal shielding layer be covered on the 4th layer of dielectric layer above, this layer 5 metal shielding layer can be any in Copper Foil, aluminium foil, free silver slurry, silver-colored carbon slurry, silver foil and the metallic composite.
The soft arranging wire of [claim 4] adjustable impedance as claimed in claim 1 is characterized in that: the thickness of described the 4th layer of dielectric layer can be regulated according to the characteristic impedance that soft arranging wire will reach.
The soft arranging wire of [claim 5] adjustable impedance as claimed in claim 1 is characterized in that: described the 4th layer of dielectric layer can be chosen the different materials with differing dielectric constant.
The soft arranging wire of [claim 6] adjustable impedance as claimed in claim 5 is characterized in that: the dielectric material that described soft arranging wire can select to have differing dielectric constant is according to demand regulated the characteristic impedance of soft arranging wire.
The soft arranging wire of [claim 7] adjustable impedance as claimed in claim 1 is characterized in that: described soft arranging wire is used for connecting LCD and motherboard by electric connector.
The soft arranging wire of [claim 8] adjustable impedance as claimed in claim 7, it is characterized in that: the grounded parts of the electric connector that described layer 5 metal shielding layer can be connected with soft arranging wire electrically connects, thereby makes the ground connection better effects if of the combination of this soft arranging wire and electric connector.
The soft arranging wire of [claim 9] adjustable impedance as claimed in claim 1, it is characterized in that: described second layer electric wire layer is made up of the tin-coated copper electric wire, its two ends are exposed outside, and remainder is all coated by ground floor insulating barrier and three-layer insulated layer, and and external insulation.
The soft arranging wire of [claim 10] adjustable impedance as claimed in claim 1 is characterized in that: the soft arranging wire of described adjustable impedance can be used for the requirement characteristic impedance under the environment of 85-115 Ω.