Biaxially oriented polyester film

A biaxially oriented polyester film in the form of a laminated film comprising;

• a biaxially oriented polyester base film having a phosphorus element content of 0 to 170 ppm and a terminal carboxylic acid content of not more than 26 equivalents/t, and
• a coating layer formed on at least one surface of the biaxially oriented polyester base film which comprises a polyurethane having a polycarbonate skeleton or a polyether skeleton and a crosslinking agent,
• wherein the laminated film has a haze value of not more than 10%, wherein the coating layer comprises no polyester-based. resin and polyester polyurethane resin, or the coating layer comprises a polyester-based. resin and polyester polyurethane resin in the amount of less than 10% by weight based on the weight of coating layer,
• the laminated film further comprising a solar cell sealing resin layer directly laminated on the coating layer, which solar cell sealing resin layer comprises at least one member selected from the group consisting of ethyiene-vinyl acetate copolymer, polyvinyl butyral, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers and ethylene-α-olefin copolymers.