Modular screen structure for the demarcation of spaces comprising: - a base element consisting of a pair of vertical uprights (12a, 12b) designed to support a first panel; - an upper element consisting of a pair of vertical uprights (22a, 22b) designed to support a second panel, said upper element being designed to be raised and lowered with respect to said base element; wherein each of the vertical uprights (12a, 12b) of the base element has a profile such as to slidably receive the profile of a respective vertical upright (22a, 22b) of the upper element and is provided with a vertical opening designed to allow the sliding of the panel of the upper element; said modular screen structure being characterised in that the sliding of the upper element is regulated by two electromechanical actuation units placed in the vertical uprights (12a, 12b; 22a, 22b), each of said electromechanical actuation units being formed by: - an electric motor placed in the lower part of the vertical upright (12a, 12b) of the base element; - a worm screw (102a, 102b) actuated by said electric motor; - a nut (103a, 103b) fixed to the profile of the vertical upright (22a, 22b) of the upper element designed to be engaged by said worm screw (102a, 102b) to allow the sliding of the upper element with respect to the base element. - a base element consisting of a pair of vertical uprights (12a, 12b) designed to support a first panel; - an upper element consisting of a pair of vertical uprights (22a, 22b) designed to support a second panel, said upper element being designed to be raised and lowered with respect to said base element; wherein each of the vertical uprights (12a, 12b) of the base element has a profile such as to slidably receive the profile of a respective vertical upright (22a, 22b) of the upper element and is provided with a vertical opening designed to allow the sliding of the panel of the upper element; said modular screen structure being characterised in that the sliding of the upper element is regulated by two electromechanical actuation units placed in the vertical uprights (12a, 12b; 22a, 22b), each of said electromechanical actuation units being formed by: - an electric motor placed in the lower part of the vertical upright (12a, 12b) of the base element; - a worm screw (102a, 102b) actuated by said electric motor; - a nut (103a, 103b) fixed to the profile of the vertical upright (22a, 22b) of the upper element designed to be engaged by said worm screw (102a, 102b) to allow the sliding of the upper element with respect to the base element. wherein each of the vertical uprights (12a, 12b) of the base element has a profile such as to slidably receive the profile of a respective vertical upright (22a, 22b) of the upper element and is provided with a vertical opening designed to allow the sliding of the panel of the upper element; said modular screen structure being characterised in that the sliding of the upper element is regulated by two electromechanical actuation units placed in the vertical uprights (12a, 12b; 22a, 22b), each of said electromechanical actuation units being formed by: - an electric motor placed in the lower part of the vertical upright (12a, 12b) of the base element; - a worm screw (102a, 102b) actuated by said electric motor; - a nut (103a, 103b) fixed to the profile of the vertical upright (22a, 22b) of the upper element designed to be engaged by said worm screw (102a, 102b) to allow the sliding of the upper element with respect to the base element. - an electric motor placed in the lower part of the vertical upright (12a, 12b) of the base element; - a worm screw (102a, 102b) actuated by said electric motor; - a nut (103a, 103b) fixed to the profile of the vertical upright (22a, 22b) of the upper element designed to be engaged by said worm screw (102a, 102b) to allow the sliding of the upper element with respect to the base element.