Patent ID: 7326914

Claim:
A light grid for measuring an object and securing a dangerous zone of a machine comprising an emitting unit having individual light emitters for directing a plurality of light beams in the form of emitted light cones approximately along a plane, a receiving unit which is spaced apart from the emitting unit and has individual light receivers for receiving light from the emitted light cones, the emitting unit and the receiving unit defining a protected zone between them, at least one of the emitting unit and the receiving unit having at least two differently formed first and second optics, the first optics generating at least one of the emitted light cone and the received light cone, the light cones having a greater dimension in a direction parallel to the plane than in a direction transverse to the plane, and the second optics generating at least one of a second emitted light cone and a second received light cone, the second light cone having an approximately circular cross-section, the first and second optics being alternatingly arranged with a spacing between them so that optical axes of the emitting unit and the receiving unit lie approximately in the plane.