Display module and display device

A display device, comprising a display module and a border, wherein the border surrounds the display module, and the display module comprises:

• a backplane, defining a receiving slot;
• a light source assembly, arranged at a bottom of the receiving slot;
• an optical substrate, snapped to an upper portion of the receiving slot, wherein a sealing cavity is defined between the optical substrate and the light source assembly;
• a coolant, received in the sealing cavity;
• a self-sealing fixation assembly, rotatably arranged on a slot wall of the receiving slot, wherein, in a first state, the optical substrate abuts against the self-sealing fixation assembly in a direction towards the bottom of the receiving slot;
• and, in a second state, the self-sealing fixation assembly is in an interference fit with the optical substrate, the self-sealing fixation assembly and the optical substrate are locked with each other to cooperatively define the sealing cavity.