BACKLIGHT DEVICE, LIQUID CRYSTAL DISPLAY DEVICE, OPTICAL MEMBER, AND LENTICULAR LENS SHEET

摘要

A backlight device has an area light source, a lenticular lens sheet (31), and a diffusion sheet (32). The area light source has linear light sources arranged next to each other. The lenticular lens sheet (31) is installed over the area light source. The lenticular lens sheet (31) has cylindrical lenses arranged next to each other in the direction in which the linear light sources are arranged next to each other, and also has flat sections each formed between adjacent cylindrical lenses. The pitch Pc of the cylindrical lenses, the width Wf of a flat section, and the height Hc of a cylindrical lens satisfy the formula (1) and formula (2). The diffusion sheet (32) is installed over the cylindrical lenses and has a haze in the range of 70% to 80%. In the backlight device, uneven luminance is suppressed and the width of viewing angle dependence of luminance in the direction of a specific axis is maintained wide. 1/16 = Wf/Pc < 1/6 (1) 5/16 = Hc/Pc = 1/2 (2)