The invention relates to the field of touch screens, in particular to an optical touch screen which comprises a touch pad, a single processing system and a photosensitive element group, wherein the photosensitive element group comprises a plurality of photosensitive elements which are connected with the single processing system. An optical touch screen light source comprises a light source, lightgenerated by the light source radiates more uniformly on the touch pad and transmits towards the outside of the touch pad, wherein transparent media are arranged on the outer surface of the touch pad. The invention also provides a contact touch pen which comprises a switch and a light emitting element, wherein the switch controls the light emitting situation of the light emitting element. The invention provides a remote touch pen as well, and the remote touch pen comprises a laser device, a power supply and a shell convenient for hand holding, wherein the laser device and the power supply arearranged in the shell, a switch is arranged between the laser device and the power supply and is arranged on the shell. The invention has strong anti-interference capability, resists greasy dirt and is applicable to occasions full of greasy dirty, such as factories, workshops, mine concessions and the like. Switching between remote touch mode and contact touch mode can be realized easily.