The disclosure is directed to a touch proximity sensing system detecting
the presence or absence of a triggering object. The system includes a
reflective optical sensor, an active surface, and a light pipe in
combination. The reflective optical sensor has an emitter for creating a
light and a receiver for detecting a reflected light of the emitter. The
active surface is suitable for receiving the triggering object, such as a
stylus or finger, or the like. The light pipe is disposed between the
reflective optical sensor and the active surface. The length of the light
pipe is such that the reflective optical sensor and the active surface
are spaced-apart from each other. The light pipe transports the light
from the emitter to the active surface. In the presence of the triggering
object, light from the emitter is reflected and the light pipe transports
the reflected light to the receiver.