TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Parameter: The density of inorganic particle (B2) in polyester layer (P2) is greater than or equal to 0.5 pieces/mm2. The density of inorganic particle (B3) in polyester layer (P3) is greater than or equal to 0.5 pieces/mm2. Preferred Composition: The inorganic particle (B2) and inorganic particle (B3) are both inorganic oxides.    TECHNOLOGY FOCUS - POLYMERS - Preferred Parameter: The bubble content rate of polyester layer (P2) and polyester layer (P3) is less than or equal to 5 vol.%. The thickness (d1) of polyester layer (P1), thickness (d2) of polyester layer (P2) and thickness (d3) of polyester layer (P3) satisfy relationship of formula d1 divide by (d2+d3)=2-25. The thickness (d2) of polyester layer (P2) and thickness (d3) of polyester layer (P3 layer) are greater than or equal to 1 mu m. Preferred Process: The biaxial orientation of polyester layer (P1) is carried out. Preferred Composition: The polyester resin (A2) has ethylene terephthalate or ethylene-2,6-naphthalene dicarboxylate as main structural component, alicyclic diol component, aromatic diol component and alkylene glycol component with greater than or equal to 3 carbons as diol component, and alicyclic dicarboxylic acid component, isophthalic acid component and aromatic polycyclic dicarboxylic acid component as dicarboxylic acid component. The sum total of content of alicyclic diol component, aromatic diol component and alkylene glycol component with greater than or equal to 3 carbons in polyester layer (P2) with respect to quantity of diol component in polyester layer (P2) is 1-30 mol%. The sum total of content of alicyclic dicarboxylic acid component, isophthalic acid component and aromatic polycyclic dicarboxylic acid component in polyester layer (P2) with respect to quantity of dicarboxylic acid component in polyester layer (P2) is 1 to 30 mol%. The polyester resin (A3) has ethylene terephthalate or ethylene-2,6-naphthalene dicarboxylate as main structural component, alicyclic diol component, aromatic diol component and alkylene glycol component with greater than or equal to 3 carbons as diol component, and alicyclic dicarboxylic acid component, isophthalic acid component and aromatic polycyclic dicarboxylic acid component as dicarboxylic acid component. The sum total of content of alicyclic diol component, aromatic diol component and alkylene glycol component with greater than or equal to 3 carbons in polyester layer (P3) with respect to quantity of diol component in polyester layer (P3) is 1 to 30 mol%. The sum total of content of alicyclic dicarboxylic acid component, isophthalic acid component and aromatic polycyclic dicarboxylic acid component in polyester layer (P3) with respect to quantity of dicarboxylic acid component in polyester layer (P3) is 1 to 30 mol%.