3D display device and display method thereof

A three dimensional (3D) display device, comprising a two dimensional (2D) display panel and a slit grating superimposed on the 2D display panel, wherein the 2D display panel includes a plurality of subpixels sequentially arranged in a row direction and a column direction;

• the slit grating includes a plurality of light-transmitting strips and a plurality of light-shielding strips which are parallel to each other and alternately and periodically arranged;
• an angle formed by a central axis of each of the light-shielding strips and the column direction is an acute angle;
• and
• an area between the central axes of two adjacent light-shielding strips is divided into a first subarea disposed on a first side and a second subarea disposed on a second side by a central axis of a light-transmitting strip between the two adjacent light-shielding strips;
• subpixels whose area falling into the first subarea is greater than ½ subpixel area are first viewpoint subpixels;
• and subpixels whose area falling into the second subarea is greater than ½ subpixel area are second viewpoint subpixels,
• an interval in the row direction between central axes of adjacent light-shielding strips is equal to a size in the row direction of an odd number of subpixels, and the odd number is three or more;
• the first subarea and the second subarea are alternately arranged in the row direction.