Why does the FPC circuit board have positive and negative layers?
For the bottom, the general is a large copper skin, then use the negative layer is very small storage space, convenient to send.
Positive layer is the data above the line and the actual line of the same; negative layer is the data line and the actual opposite.
The general circuit layer is a positive layer and the power layer is a negative layer. The negative layer is used to store and edit the data in a smaller space.
More than FPC (flexible plate), PCB also has a positive and negative layer.
