Patent ID: 8884923

Claim:
An optical touch apparatus, suitable for a display area, the optical touch apparatus comprising: at least a light source, disposed next to the display area and capable of providing a beam; at least a light guide unit, disposed next to the display area and in a transmission path of the beam, the light guide unit comprising: a light guide body, having a first surface, a second surface opposite to the first surface, at least a light incident surface connecting the first surface and the second surface, a third surface connecting the light incident surface, the first surface, and the second surface, and a fourth surface opposite to the third surface and connecting the light incident surface, the first surface, and the second surface, wherein the beam is capable of entering the light guide body through the light incident surface and is capable of being transmitted from the first surface to a sensing space in front of the display area; and a Lambertian scattering structure, disposed on at least one of the second surface, the third surface, and the fourth surface, such that the beam is scattered to the first surface and a root mean square value of differences between light intensity of a normalized light intensity distribution curve of the beam emitted from the first surface at each light emission angle and light intensity of a Lambertian normalized light intensity distribution curve at the same angle is equal to or less than 0.2; and at least an optical detector, disposed next to the display area and used to detect a change in light intensity of the beam in the sensing space.