Switchable barrier and 3D display device having thereof

A parallax barrier, comprising:

• a first substrate and a second substrate;
• a liquid crystal layer between the first substrate and the second substrate;
• at least one insulating layer on the first substrate;
• a first electrode on the second substrate;
• a second electrode and a third electrode on the insulating layer to generate electric field in order to transmit and block selectively an image;
• a plurality of first spacers on the first substrate;
• and.
• a plurality of second spacers on the second substrate,
• wherein the first spacers and the second spacers are formed in regions corresponding to each to maintain a gap between the first substrate and the second substrate,
• wherein a top surface of a first spacer from among the plurality of first spacers and a top surface of a corresponding second spacer from among the plurality of second spacers face each other, and wherein the top surface of the first spacer is spaced apart from the top surface of the corresponding second spacer by a predetermined distance in a thickness direction of the liquid crystal layer.