LIGHT PEN

摘要

A light pen which works in conjunction with an image sensor array to allow the sensor array to distinguish between a finger touch and touch by the light pen. The light pen is arranged to pass through a laser curtain or other light source undetected by the image sensor.

主权项

1. A system for determining a position on a surface, comprising:
a light source arrangement generating at least one incident light beam; a pointing device comprising: a body portion; a proximal portion at an extent of the pointing device configured to be proximal to the surface; and a light emitting unit for radiating light when actuated by contact between the proximal portion and the surface; and a light sensor arrangement configured to sense reflected light from objects interrupting the light beam and the radiated light from the light emitting unit, wherein an output from the light sensor arrangement is processed to determine the position of detected objects on the surface; and wherein the proximal portion of the pointing device is made of an admissive material that admits a substantial portion of the incident light from the light source arrangement, thereby avoiding detection of the pointing device until the light emitting unit is actuated.