Patent attributes
A hinge device can detect an open angle and an opening/closing angular velocity with high responsiveness and simple configuration. The hinge device enables rotary motion of a main-body chassis and a display chassis, and includes a first chassis shaft non-rotatably provided with respect to the main-body chassis, a second chassis shaft non-rotatably provided with respect to the display chassis, a cylindrical body into which the first chassis shaft is inserted to rotate with rotary motion thereof, a ring-type magnet non-rotatably fixed to the cylindrical body, a sensor that detects a movement of the magnet associated with the rotary motion from the change of magnetism, and a controller that reads a signal from the sensor to calculate an open angle and an opening/closing angular velocity.