Panasonic has commercialised its Low Transmission Loss Flexible Multi-layer Circuit Board Materials, suitable for high-speed large-volume data transmission and thinner designs of mobile devices, including smartphones and tablet computers.
The combination of a liquid-crystal polymer (LCP) core material and a bonding sheet material that can be laminated at a low temperature and stored at room temperature will considerably ease the manufacture of high-frequency flexible multi-layer circuit boards.
Existing coaxial cables used for large-volume transmission are thick, so they present an obstacle to making mobile devices thinner. Low transmission loss flexible multi-layer circuit boards are of increasing potential as a solution that achieves both large-volume data transmission and a thin design, but they face many restrictions in how they should be handled, due to the characteristics of the materials they incorporate. This means they require special facilities for manufacturing.
Using its resin design technologies, Panasonic has developed a bonding sheet that can be laminated at a low temperature of less than 200°C and stored at room temperature. This eliminates the need for special facilities for high-temperature lamination and refrigerated storage for bonding sheets. The company has also achieved high adhesiveness of LCP and low profile copper foil for the LCP core material by using its unique laminating techniques. Although existing flexible core materials using polyimide and so on are usable for only low-speed transmission, the new material, due to its low transmission loss property can also be used for high-speed transmission of large-volume data.
- Low transmission loss and compatibility with USB 3.1 Gen 2 (10 Gbps) enable the transmission of large-volume data at higher speeds
Transmission loss: -2 dB/100 mm @ 6 GHz.
Core material: Dielectric constant: 2.9 @ 10 GHz, dissipation factor: 0.002 @ 10 GHz
Bonding sheet: Dielectric constant: 2.2 @ 10 GHz, dissipation factor: 0.001 @ 10 GHz
- Flexible multi-layer circuit board adopts a 3-layer structure with multiple of signal lines at a thickness of 0.2 mm, allowing further thinning of mobile devices.
Total board thickness: 0.2 mm or less
- Circuit board material that can be laminated at a low temperature and stored at room temperature makes manufacturing of flexible multi-layer circuit boards easier.
Lamination temperature: 180 – 200°C, existing bonding sheet: 300°C
Room-temperature storage: 23 (±5) °C, existing bonding sheet: refrigerated storage: 5°C or below