Light curtain for 2D large-area object detection.

Fluorescent foils are used with silicon photodiodes for large-area detection of objects, when combined with lasers forming a light curtain. An object entering the detection area penetrates the light curtain and casts shadows onto the fluorescent foils. Using a simple mathematical algorithm, the position of the object is detected with high speed.

Video-speed detection of the absolute position of a light point on a large-area photodetector based on luminescent waveguides.

A large-area photosensor is presented that uses the coupling of light into the planar waveguide mode of a polycarbonate foil by luminescent dyes to extend the active area of silicon photodiodes attached to the surface of the foil in a regular pattern. The photodiode signal is directly related to the distance between the point where light is coupled into the foil and the photodiode, thus enabling a precise recovery of the position of a localized light signal hitting the foil. We present a large-area device that can trace the movement of a light point generated by a laser pointer hitting its surface.