BIAXIALLY ORIENTED UV-RESISTANT SINGLE OR MULTILAYER POLYESTER FILM HAVING ANTIREFLECTIVE COATING (ANTIGLARE) ON ONE SURFACE AND HAVING TRANSMITTANCE OF AT LEAST 93.5%
PROBLEM TO BE SOLVED: To provide a biaxially oriented polyester film having a high transmittance for rays of at least 93.5%, which shows no significant yellowing or no brittleness or cracks on a surface and is free from degradation in mechanical and optical properties that may cause troubles in use, even when the film is used outdoors for a number of years.SOLUTION: The polyester film comprises: a single-layer or multilayer base polyester film; an antireflective film disposed on an A side surface of the base polyester film; and an antireflective film the same as the antireflective film disposed on the A side or another antireflective outer layer, disposed on a C side surface opposite to the A side surface. The antireflective film or another antireflective outer layer disposed on the C side surface has a refractive index lower than the refractive index of the base polyester film. All layers of the base polyester film contain a UV stabilizer. The polyester film has a ray transmittance of at least 93.5%.SELECTED DRAWING: None【課題】屋外で何年も使用されても、目立った黄変が起こらず、表面の脆化やクラックが生じず、使用に支障となるような機械的および光学的性質の劣化が生じない、93.5%以上の高い光線透過率を有する二軸延伸ポリエステルフィルムを提供する。【解決手段】単層または多層から成るベースポリエステルフィルムと、当該ベースポリエステルフィルムのA側面に設けられる反射防止性膜と、A側面とは反対側のC側面に設けられる、A側面に設けられた反射防止性膜または他の反射防止性外層とから成るポリエステルフィルムであって、C側面に設けられた反射防止性膜または他の反射防止性外層の屈折率がベースポリエステルフィルムの屈折率よりも低く、ベースポリエステルフィルムの全ての層はUV安定剤を含有し、ポリエステルフィルムの光線透過率が93.5%以上であることを特徴とするポリエステルフィルム。【選択図】なし