Optical substrate and manufacturing method thereof, display device and 3D display system

The invention provides an optical substrate and a manufacturing method thereof, a display device and a 3D display system, and relates to the technical field of 3D display, the optical substrate is used for being matched with a display substrate, and the optical substrate comprises a transparent substrate; the alignment layer is positioned on one side of the transparent substrate; the liquid crystal layer is located on the side, away from the transparent substrate, of the alignment layer; wherein the liquid crystal layer comprises a plurality of optical areas, the sizes of the optical areas are pixel-level sizes or sub-pixel-level sizes, the pixel-level sizes correspond to the sizes of pixel areas on the display substrate, and the sub-pixel-level sizes correspond to the sizes of sub-pixel areas in the pixel areas; wherein the azimuth angles of the liquid crystals in every two adjacent optical areas in the plurality of optical areas are different, so that one optical area is a right-handed circularly polarized light area, and the other optical area is a left-handed circularly polarized light area.