Nippon Mektron Ltd exhibited a flexible substrate that can be three-dimensionally formed at JPCA Show 2010, which took place from June 2 to 4, 2010, in Tokyo.
The flexible substrate, "3D Forming FPC," consists of thermoplastic liquid crystal polymer (LCP) and copper foil. After the substrate is formed into a desired shape, it is heated and then cooled. As a result, it can maintain the shape.
Nippon Mektron plans to complete the technology development within fiscal 2010 and start volume production in fiscal 2011.
The 3D Forming FPC can realize a stretchable printed circuit board and three-dimensional wiring by, for example, folding it like pleats or making a spiral structure. The company expects that the 3D Forming FPC will be used for the joints of a robot, etc.
This time, Nippon Mektron prototyped an LED light bulb with three-dimensional wiring. The light bulb has a wide range of light radiation because its LED modules are embedded facing various directions. When a thick copper foil layer is added to the wiring layer, heat can be easily radiated from the LED module, the company said.
It is possible to easily embed a printed board by forming a flexible printed circuit board that fits in a small space inside a device, Nippon Mektron said. And the company exhibited a curved board printed with an antenna pattern and a flexible substrate that fits the shape of a mobile phone.
The LCP used for the 3D Forming FPC can tolerate reflow temperatures of up to 260°C. The thermal conductivity, water absorption rate and dielectric loss tangent of the LCP are 0.5W/m·K, less than 0.04% and 0.0025, respectively, while those of polyimide are 0.2W/m·K, 1.5% and 0.009.