| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester film having excellent economic efficiency, film formability, whiteness, reflectivity, lightness, and surface shape, and to provide a surface light source having excellent brightness property and brightness irregularity preventive performance at a low cost by using the polyester film.SOLUTION: A polyester film has a 60° glossiness of 60% to 120% and 20° and 85° glossiness of 3% to 60%, and in the polyester film, a difference between the 60° glossiness and the 20° and 85° glossiness is no less than 20%. The film has protrusions on a surface thereof, and in the film, a distance Dh from an apex of each protrusion to a root is 10-30 μm, and a distance Dw of the protrusion in a width direction perpendicular to the distance Dh is 10-30 μm. The protrusions are formed by coating with a coating agent containing particles and the number of the protrusions is 500 to 1,000 pieces per 1 mmof the film surface.SELECTED DRAWING: None |
