Touch screen

Apparatus comprising:

• a touch panel, formed of a dielectric material, to carry terahertz radiation and having a touch surface, the terahertz radiation having a frequency range between 0.1 terahertz and 10 terahertz;
• and
• a touch controller coupled to an antenna, the antenna being coupled to the dielectric material, and the antenna and the touch panel being formed over a single substrate;
• the touch controller being arranged to:
• transmit a pulse of terahertz radiation through the touch panel and the antenna to generate an employable evanescent field in a region adjacent to the touch surface;
• receive a reflected pulse generated by an object located within the region of the employable evanescent field;
• and triangulate a position of the object on the touch surface, based at least in part on the reflected pulse.

A method comprising:

• transmitting a pulse of terahertz radiation through a touch panel formed of a dielectric material, the pulse generating an employable evanescent field in a region adjacent to a touch surface of the touch panel, and the terahertz radiation having a frequency range between 0.1 terahertz and 10 terahertz;
• generating a plurality of reflected pulses, including a first reflected pulse is generated by an object located within the region adjacent to the touch surface of the touch panel and within the employable evanescent field;
• and
• triangulating a position of the object on the touch surface of the touch panel, based at least in part on the reflected pulses.