| 摘要 |
PROBLEM TO BE SOLVED: To provide a double-sided flexible circuit board suitable for a mobile phone that is suited to the transmission of high-frequency signals and is provided with a folding part to make the unit thinner, to prevent the disconnection or breakage of a conductor, and to achieve a high-density circuit board. SOLUTION: The double-sided flexible circuit board for bending use is provided with a conductor circuit 2 and a cover material 1 on both sides of an insulating layer 3. In this case, the insulating layer is formed of a liquid crystal polymer film of 10-100μm in thickness, and the cover material is formed of only a liquid crystal polymer film with a thermal deformation temperature different from that of the insulating layer. The double-sided flexible circuit board for bending use is also provided with a surrounding section of which the copper foil stress value Y is in a range of 0.5-3% when using, Y being calculated by formula (1): Y(%)=(t<SB>Cu</SB>+1/2 t<SB>LI</SB>)/(r+t<SB>CL.</SB>+t<SB>Cu</SB>+1/2 t<SB>LI</SB>)×100 (wherein, t<SB>LI</SB>: thickness of the insulating layer; t<SB>CL.</SB>: thickness of the cover material; t<SB>Cu</SB>: thickness of the copper foil; r: bending radius of the surrounding section). COPYRIGHT: (C)2011,JPO&INPIT
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