Optical sheet, optical sheet manufacturing system, and optical sheet cutting machine

An optical sheet to be used as a screen on which an image is projected from an image projector, comprising:

• optical sheet members which are substantially identical and which each have a major surface, and whose optical properties over the respective major surfaces vary cyclically along a first direction and are substantially identical along a second direction orthogonal to the first direction;
• wherein a region of the major surface of each of the optical sheet members includes undulations extending along the second direction;
• wherein said optical sheet is produced by joining the plurality of optical sheet members with respective end surfaces thereof which are substantially perpendicular to the respective major surfaces thereof meeting each other as joint surfaces;
• and
• wherein the undulations of respective ones of the optical sheet members meeting at the joint surfaces have phases which are synchronized with each other so that optical properties of the joint surfaces are substantially identical to each other within a predetermined permissible range.