BigPatents India

A device to detect holes in a continuously winding strip of material (arrow B) of the type formed of a vertical frame (100) which, placed in the path of the strip of material via a horizontal slot (110) delimiting said frame (100) into two upper (100a) and lower (100b) bodies each opening onto said slot (110) via windows opened opposite one another, the upper body (100a) intended to support a first optical sub-assembly (200) for emission for a source of light in the direction of said strip passing below it, and the lower body (100b) intended to support a second optical sub-assembly (300) for reception for said light emitted by the first optical subassembly (200) and able to filter through the holes in the strip of material passing above it, wherein the above-mentioned optical emission sub-assembly (200) is constituted by so-called laser radiation, a stimulated emission of radiation and the above-mentioned optical reception subassembly (300) is constituted by photodiodes (310a and 310b) sensitive to the low luminous flux emitted by the laser radiation.