Touch screen

A touch screen, comprising:

• a display panel,
• a touch-sensing part, disposed on a light emitting side of the display panel, having a touch-sensing surface and comprising:
• a light-emitting device, used to provide at least one positioning light and at least one high-energy light;
• and
• a light receiver, used to detect a change of the positioning light on the touch-sensing surface in response to a touch action and determine a position on which the touch action occurs on the touch-sensing surface;
• a biosensor, used to determine whether there is a living body getting close to the touch-sensing surface;
• and
• a controller, used to drive the light-emitting device to selectively provide the positioning light and/or the high-energy light to the touch-sensing surface according to determinations of the biosensor;
• wherein the light-emitting device further comprises a wavelength modulator driven by the controller according to the determination of the biosensor and considering time intervals of which the living body not getting close to the touch-sensing surface.