Resin Sheet, Direct Backlight Unit, and Direct Backlight Type Liquid Crystal Display

A resin sheet having a thickness of 1 to 5 mm, having recesses formed on one surface thereof, the recess being selected from the group consisting of a multi-sided pyramid shape, a truncated multi-sided pyramid shape, a conical shape, a truncated conical shape and a severed sphere shape,

• having an angle a which satisfies 10°≦α≦40° or 50°≦α≦80° when the angle α is formed by a side face of the recess having a multi-sided pyramid shape or a truncated multi-sided pyramid shape and a plane having the opening of the recess thereon or when the angle α is formed by the generatrix of the recess having a conical shape or a truncated conical shape and a plane having the opening of the recess thereon, and satisfying at least one of the following conditions (1) and (2).
• (1) The above recesses form a number of row groups, wherein each row group which constitue the number of row groups comprises a number of rows adjacent to each other, each row comprises the recesses arranged in a line, and each row group is adjacent to other row groups via areas free of the recesses.
• (2) Severed-sphere-shaped projections are formed on the surface opposite to the surface having the above recesses formed thereon.