A head-mounted device for reducing symptoms of cybersickness, adapted to be worn on a user's head and to be used cooperatively with a head-mounted display for stimulating a vestibular perception of a vestibular system of the user, said head-mounted device comprising:
- a main shell adapted to be mounted on the user's head, and including a first tube body, a second tube body and a third tube body that are adapted to be respectively disposed at the top of the user's head, the back of the user's head and one of the user's ears, said first, second and third tube bodies being arc-shaped, having arc-shaped central axes which respectively define imaginary first, second and third planes, and being fixedly connected to one another in a manner that the first, second and third planes are perpendicular to one another, each of said first, second and third tube bodies having opposite closed ends, for each of said first and second tube bodies, each of said closed ends being adapted to be disposed proximal to a respective one of the user's ears;
- and
- a stimulation unit including a first component, a second component and a third component, each of said first, second and third components being received in a respective one of said first, second and third tube bodies, and being configured to be movable in at least one of rolling, sliding and flowing manners in the respective one of said first, second and third tube bodies;
- wherein when rotation of the user's head drives at least one of said first, second and third components of said stimulation unit to move in the respective one of said first, second and third tube bodies, said at least one of said first, second and third components is adapted to generate and transmit a stimulation force, through one of said closed ends of the respective one of said first, second and third tube bodies, to the vestibular system of the user for stimulating the vestibular perception of the user;
- wherein each of said at least one of said first, second and third components is composed of a rigid body or a fluid;
- wherein when each of said at least one of said first, second and third components is composed of the rigid body, the stimulation force is proportional to an angular acceleration of the user's head, a total mass of the rigid body, and a radius of curvature of the respective one of said first, second and third tube bodies;
- and
- wherein when each of said at least one of said first, second and third components is composed of the fluid, the stimulation force is proportional to the angular acceleration of the user's head, the radius of curvature of the respective one of said first, second and third tube bodies, an inner cross-sectional area of the respective one of said first, second and third tube bodies, and a density of the fluid.