4 Layer Kapton Flexible PCB Board

1.Air Gap - Through the process of selective bonding, increased flexibility is achieved by "unbonding" layers so they are allowed to flex freely.

2.Controlled Impedance - With increasing signal switching speeds, engineers need to understand and control the impedance of traces. With short signal transition times and high clock rates of modern digital circuitry, traces need to be considered transmission lines instead of simple interconnections. 

3.Graphic Overlays – Graphic Overlays can be placed over flex circuits, rigid boards or membrane switches. The overlays provide the user interface with the underlying circuit and typically are used in conjunction with LEDs, LCD displays or dome switches mounted on thie circuits. The overlays are made from polycarbonate, polyester or acrylic.

4.Laser Skived Slots  -  Flexible Circuit has dramatically improved this process by utilizing a top-of-the-line laser beam with extremely precise depth control to accurately cut the underlying substrate of a flex circuit. Precise laser beams can skive circuit openings with the utmost precision.

5.Shielding – Shielding is applied when an application requires limits in electromagnetic and/or electrostatic interference. Protective shielding can be patterned or solid.

6.Stiffeners – Stiffeners are applied to flex circuits where additional support is needed such as areas of component assembly or underneath exposed traces that will be plugged in for connection. Common stiffeners are FR4 and polyimide.