Optical film set, backlight module and display device

An optical film set configured to guide light from a light guide plate of a backlight module, wherein the optical film set comprises:

• a lower prism film, wherein the lower prism film has a plurality of lower prism structures, and each of the lower prism structures extends along a first direction;
• an upper prism film disposed above the lower prism film, wherein the upper prism film has a plurality of upper prism structures, and each of the upper prism structures extends along a second direction, wherein the second direction is different from the first direction, and there is an included angle between the second direction and an extending direction of a light-incident surface of the light guide plate, wherein the included angle is in a range from 25 degrees to 50 degrees or a range from 130 degrees to 155 degrees including the end point values;
• a lower diffuser disposed under the lower prism film;
• and
• an upper diffuser disposed above the upper prism film, wherein the upper diffuser comprises a plurality of diffusion particles, and the diffusion particles of the upper diffuser make the upper diffuser have a haze smaller than 30% but not including the end point value;
• wherein a haze ratio of the lower diffuser to the upper diffuser is ranging from 1.6 to 6 including the end point values.