A usage example of the "Stretchable FPC"
A usage example of the "Stretchable FPC"
[Click to enlarge image]
When the button is pressed, the lamps turn on.
When the button is pressed, the lamps turn on.
[Click to enlarge image]

Nippon Mektron Ltd exhibited a stretchable flexible printed circuit board for reference at JPCA Show 2011, which took place from June 1 to 3, 2011, in Tokyo.

At the show, the company showcased a prototype of the circuit board, "Stretchable FPC," expecting that it will be attached to an arm of a robot or a human body. If sensors are embedded in the Stretchable FPC, for example, a robot can be stopped when it touches an object.

The prototyped Stretchable FPC has a structure in which copper (Cu) lines are located between two 150μm-thick elastomer resin sheets. Because existing flexible printed circuit boards use polyimide, they do not have flexibility.

With the elastomer resin, the Stretchable FPC features a flexibility of 30% or higher. Also, Nippon Mektron used wavelike Cu lines so that they can withstand stretches.

In addition to its flexibility, elastomer resins have an excellent abrasion resistance. They are currently more expensive than polyimide, but the company said, "Their prices will decrease once we start volume production."

For the future, Nippon Mektron plans to evaluate the durability, etc of the Stretchable FPC after repeatedly stretching it.