Optical sheet, light controlling member, surface light source device, image source unit, and display

An optical sheet that is made of a plurality of laminated layers, the optical sheet comprising:

• an optical functional layer that is one of a plurality of the laminated layers;
• and
• an optical element layer that is another one of a plurality of the laminated layers,
• wherein the optical functional layer has a plurality of light transmissive portions extending in one direction, the light transmissive portions being arranged at intervals in a direction different from the one direction, and a light absorbing portion that is arranged between respective adjacent light transmissive portions,
• the optical element layer extends so as to be offset from the one direction at an angle of 0° to 45° in a front view of the optical sheet, the optical element layer having a plurality of unit optical elements that are ridges aligned in a direction different from a direction in which the optical element layer extends,
• wherein Pmx is no more than 10000 (μm),
• wherein an aligning pitch of the light transmissive portions is Pa (μm), an aligning pitch of the unit optical elements is Po (μm), and a and b are each integers of 1 to 10,
• wherein Pm=|(a·Pa·b·Po)/(a·Pa−b·Po)|, and
• wherein a largest Pm obtained by all combinations of a and b for Pa and Po is Pmx (μm).