Tensioning device, base, clamp and method for clamping mask plate

A tensioning device, comprising:

• a base configured to carry a mask plate;
• a clamp configured to clamp the mask plate;
• a deformation adjusting assembly provided on the base or on the clamp;
• wherein the deformation adjusting assembly comprises an electromagnet and a current control unit, and is configured to adjust a deformation of an end portion of the mask plate protruding from the base in a direction of gravity when the base carries the mask plate, so as to make the deformation less than a preset deformation threshold;
• and a measuring unit configured to measure an initial deformation of the end portion of the mask plate protruding from the base in the direction of gravity, the initial deformation is a deformation of the end portion of the mask plate protruding from the base in the direction of gravity before being adjusted by the deformation adjusting assembly;
• wherein the current control unit is configured to acquire the initial deformation from the measuring unit and determine an output current according to the initial deformation, and output the output current to the electromagnet, such that a magnitude of the output current output by the current control unit is equal to a product of the initial deformation and a preset ratio;
• and a resulting electromagnetic force of the electromagnet being powered by the output current is less than or equal to a gravity applied to the end portion of the mask plate protruding from the base to prevent the protruding end portion from being bent upward due to excessive electromagnetic force.