Dancing is a vibrant and expressive form of art, and the right equipment can elevate the performance. A pair of well-designed dancing shoes makes a big difference. Our company recently partnered with a Japanese design firm to co-develop a smart LED dancing shoe, where our key contribution was the design and fabrication of the flexible printed circuit (FPC) board that powers the lights.

This Japanese partner, renowned for customized product development, discovered us through a technology exhibition in Japan. Together, we aimed to build an ultra-flexible and durable FPC that could withstand continuous movement while ensuring consistent LED performance.

FPC Bending Design Guidelines

Here are some essential considerations we implemented based on dynamic and durable flex board design principles:

  • Minimum Bending Radius:
    • 2-layer flexible PCB with 300µm thickness: r = 10 × 300µm = 3mm
    • For dynamic installation (400µm thickness): r = 25 × 400µm = 10mm
  • Design Techniques for Durability:
    • Avoid placing plated-through holes or pads in the bending zone
    • Ensure conductor traces run perpendicular to the bending axis

      Flex Board Design for Dancing Shoes

    • Use blind conductors in open regions within the bend
  • Dynamic Bending Optimization:
    • Incorporate drill holes or slots
    • Avoid copper edges at the bending site
    • Add copper stiffeners to aid bending
  • Durable Bending (One-time bends):
    • Narrow contours and stabilize with additional copper
    • Drill holes or use slots to manage strain
  • Multi-layer Flex Arrangement:
    • For designs with two or more flexible layers, conductor traces should be alternately arranged on the front and back sides to minimize stress accumulation.

Final Product Specifications

Flex Board Design for Dancing Shoes

  • Layers: 2-layer flexible PCB
  • Surface Finish: ENIG (Electroless Nickel Immersion Gold)
  • Adhesive: Special glue-filling treatment
  • Thickness: 0.15mm (excluding reinforcement)
  • Copper Thickness: 2oz
  • Assembly: SMT-assembled LEDs on the flex board

    Flex Board Design for Dancing Shoes

Technical Challenge

One of the most challenging aspects of this design was controlling the glue-filling thickness. We needed to ensure the glue provided the desired softness without compromising structure or LED stability. After multiple rounds of testing, we identified a suitable epoxy glue that met both flexibility and adhesion requirements.

Product Functionality

Once fully charged, the dancing shoe emits colorful LED lights. The frequency and brightness of the lights change based on the speed and intensity of the wearer’s movements, adding a dynamic visual element to every step.

This project showcases our strength in high-flexibility PCB design, turning motion into an engaging light performance.