US Patent 10048806 Optical touch system and optical touch apparatus thereof

An optical touch system including an optical touch apparatus and an optical touch stylus is provided. The optical touch apparatus includes a curved operation surface and a plurality of optical sensors. The curved operation surface has a vertex. The optical touch stylus performs a touch operation on the curved operation surface, and has a tip portion for generating a light signal. The optical sensors are arranged on a side of the curved operation surface based on a reference line. The optical sensors are configured to receive the light signal to sense the touch operation of the optical touch stylus performed on the curved operation surface. A surface sag exists between each of the optical sensors and the vertex. A difference between a tip length of the optical touch stylus and a distance of two selected surface sags is not smaller than a region parameter of the optical touch system.