Flexible PCBs are generally known for being thin and easily bendable. However, from the perspective of minimum bend radius and flex resistance, there was a risk of breakage due to repetitive or excessive bending.
By using a Tomoe type kirigami structure as shown in the figure, the wiring can be bent 180˚ without creasing the wiring.(*)
The Tomoe type cut pattern allows a movement of 180˚ without folding or leaving a crease.
The lack of creases reduces the risk of breakage, and it can be applied to sheets made of thick or hard materials to make them easier to bend or bend 180 degrees. It can also be applied to mounting circuit boards on origami, and to making flexible PCBs with thick and durable materials.
Stretchable LED lamp wrapped around a tube using a Tomoe type structure.
Tomoe type kirigami structure for 180˚ bends
From the video
『What I want to show you today is a Tomoe type kirigami structure that allows for 180˚ bends.
By adding these N shaped Tomoe type cutlines, no fold marks are added (to the wiring parts), greatly reducing the risk of disconnection and allowing for 180˚ bends.
Normally, for something as hard and thick as this, bending it in half at 180˚ wouldn’t be possible.
Tomoe type cutlines are added by laser processing to allow for 180˚ bends, like so.
This is an actual example of Tomoe type kirigami structure applied to a LED lamp.』