Patent ID: 11977251

Abstract:
A backlight module including a light guide plate, a light source, an upper prism sheet, and a lower prism sheet is provided. The light guide plate has a light incident surface and a light emitting surface. The upper prism sheet is disposed at a side of the light emitting surface of the light guide plate. The upper prism sheet includes an upper substrate and first prism microstructures. Cross-sections of the first prism microstructures are isosceles triangles, and apex angles thereof fall within a range of 80 to 90 degrees. The lower prism sheet is disposed between the light guide plate and the upper prism sheet. The lower prism sheet includes a lower substrate and second prism microstructures. Cross-sections of the second prism microstructures are isosceles triangles, and apex angles thereof fall within a range of 100 to 130 degrees.