Fig. 4

ELGM design rules. a ELGM design parameters. L is the length between two hinged ends, and H is the height between the red and blue lines. The red line shows the initial posture of the ELGM which corresponds to the opening phase of the eyelid, and the blue line shows the deformed posture of the ELGM, which corresponds to the eyelid closure phase of the ELGM. H refers to the width between the upper and lower eyelids, l is the length of the handle part of the ELGM, and \(\psi\) is the inclination of the handle. b ELGM fixed on an eyeglass-type frame. \(\phi\) is the angle between the rotation axes on the handle parts, \(L'\) is the width between the fixed ends, and \(\theta\) is the rotational input angle transmitted by the pulley mechanism to deform the ELGM