Patent ID: 8816993

Claim:
A touch input system, comprising: a stylus, comprising: a pipe, having a front end, a back end opposite to the front end and an opening formed at the front end, wherein a diameter of the opening is smaller than a diameter of the pipe; a battery module, disposed within the pipe; a touch portion, sliding disposed at the opening and having an emitting element, wherein at least a part of the touch portion is located in the pipe; a detector, disposed between the battery module and the touch portion, and used to detect a signal from the emitting element to obtain a variation of a distance between the touch portion and the detector; a protrusion, disposed within the pipe; and a switch element, fixed and electrically connected to the touch portion, and has an elastic element, wherein the touch portion is driven to move toward the back end by an exertion force, the switch element is pushed forward to contact the protrusion for actuating the touch portion to emit a light signal, and the elastic element is compressed between the touch portion and the protrusion; and a display device, comprising: a display region, detecting the light signal to locate a touch position when the touch portion is exerted on the display region, wherein the display region displays a line width according to the variation of the distance detected by the detector.