Patent Application
20100314155
1. Technical Field
The present disclosure relates to signal cables and, particularly, to a low voltage differential signal (LVDS) cable.
2. Description of Related Art
In an LVDS transmission system, LVDS cables are often used to transmit high-frequency differential signals between liquid crystal displays (LCDs) and motherboards of computers. The LVDS transmission system must meet a requirement of lowering electromagnetic interference and eliminate noise. However, ordinary LVDS cables are flexible flat cables (FFCs), which cannot achieve a good transmission quality.
Referring to
Referring to
Insulation material 122 is packaged around each power wire 12. Each twisted line 14 includes a pair of differential signal wires 142, 144 and a ground bare wire 146. The pair of differential signal wires 142, 144 and the ground bare wire 146 are twisted together to form a triple-twisted line. Insulation material 1422 is packaged around each differential signal wire 142. Insulation material 1442 is packaged around each differential signal wire 144. A layer of material 148 conductive on one side, such as a material with aluminum foil on the one side, is packaged around each signal transmission twisted line 14, and the conductive side of the layer of material 148 is attached to the signal transmission twisted lines 14. A layer of material 18 conductive on one side, such as conductive fabric, is packaged around the cable body 10, and the conductive side of the layer of material 18 is attached to the cable body 10.
An arrangement of the two power wires 12, the four twisted lines 14, and the nine ground bare wires 16 in the cable body 10 is: the two power wires 12 are arranged in a center of the cable body 10, the four twisted lines 14 are equidistantly arranged around the two power wires 12, and the nine ground bare wires 16 are equidistantly arranged around the four twisted lines 14.
In one embodiment, a length of the cable body 10 is about 360 mm±10 mm. An impedance of each twisted line 14 is about 100Ω±5Ω. A twist density of each signal transmission twisted line 14 is about three sections per centimeter. A thickness range of the layer of material 148 is about 0.15 mm-0.3 mm. A surface resistance of the layer of material 148 is less than or equal to 0.03Ω. A thickness range of the layer of material 18 is about 0.15 mm-0.3 mm. A surface resistance of the layer of material 18 is less than or equal to 0.07Ω. In other embodiments, the above parameters can be changed according to requirements.
In one embodiment, a layer of insulation fabric 50 is packaged around the second connector 30 and a part connecting the second connector 30 of the cable body 10, to avoid the LDVS cable 1 short-circuiting. The second connector 30 includes a ground wire 40, a first end of the ground wire 40 is connected to any one ground bare wire arranged in the cable body 10. A ground ring 42 is connected to a second end opposite to the first end of the ground wire 40. The ground ring 42 can be used to be mounted on a grounded portion of the motherboard to provide a ground path for the LVDS signal cable 1.
The LVDS cable 1 has high mutual inductances and short circuit return paths, therefore noise generated from the LVDS cable 1 is very small. Referring to
It is to be understood, however, that even though numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, the disclosure is illustrative only, and changes may be made in details, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200910303117.6 | Jun 2009 | CN | national |
