Stiffener sheet and flexible printed circuit board using the same
A stiffener sheet for flexible printed flexible printed circuit boards, includes alternately laminated polyimide layers and polyamideimide layers, wherein a molecular structure of the polyamideimide is represented by the following formula: wherein Ar and Ar′ represents different substituted aromatic groups.
1. A stiffener sheet for a flexible printed circuit board, comprising: a plurality of polyimide layers and a plurality of polyamideimide layers, the polyimide layers and the polyamideimide layers alternately stacked one on another, wherein a molecular structure of the polyamideimide is represented by the following formula:
wherein Ar and Ar′ represent different substituted aromatic groups.
2. The stiffener sheet as claimed in claim 1 , wherein the number of the polyimide layers is equal to the number of the polyamideimide layers.
3. A stiffened flexible printed circuit board, comprising:
a flexible printed circuit board comprising a contact surface; and
a stiffener sheet attached on the contact surface, wherein the stiffener sheet comprising a plurality of polyimide layers and a plurality of polyamideimide layers, the polyimide layers and the polyamideimide layers alternately stacked one on another, wherein a molecular structure of the polyamideimide being represented by the following formula:
wherein Ar and Ar′ represent different substituted aromatic groups.
4. The stiffened flexible printed circuit board as claimed in claim 3 , wherein the number of the polyimide layers is equal to the number of the polyamideimide layers.
5. The stiffened flexible printed circuit board as claimed in claim 3 , further comprising an adhesive layer sandwiched between the stiffener sheet and the flexible printed circuit board.
6. The stiffened flexible printed circuit board as claimed in claim 5 , wherein the adhesive layer is comprised of polyamideimide.
7. A stiffened flexible printed circuit board, comprising:
a flexible printed circuit board; and
a stiffener sheet attached to the flexible printed circuit board, wherein the stiffener sheet comprising a plurality of polyimide layers and a plurality of polyamideimide layers, wherein a molecular structure of the polyamideimide being represented by the following formula:
wherein Ar and Ar′ represent different substituted aromatic groups.