Optical sheet laminate, backlight unit, liquid crystal display device, information equipment, and production method for backlight unit

A diffusion sheet laminate in a backlight unit, the diffusion sheet laminate comprising:

• a plurality of diffusion sheets each having surfaces, at least one of which has a plurality of recesses having a substantially inverted quadrangular pyramid shape,
• wherein:
• the plurality of recesses have an apex angle of 95° or more,
• the plurality of recesses are arrayed in a two-dimensional matrix, and
• the diffusion sheet laminate is built under a pair of prism sheets having prism extending directions perpendicular to each other in the backlight unit, a prism extending direction of a lower prism sheet which is one of the pair of prism sheets and is closer to the plurality of diffusion sheets and an arrangement direction of the plurality of recesses on an upper diffusion sheet which is one of the plurality of diffusion sheets and is closest to the lower prism sheet intersect with each other at an angular difference of 30° or less.