Non-imaging optical corner turner
View Patent ↗The present invention provides a device and method to efficiently turn light from an optical fiber around a corner while avoiding the frustrated-TIR loss that would occur if the fiber were bent. The invention uses non-imaging optics which efficiently deal with beam divergence half-angles less than 90°. By recognizing that most light from a fiber optic source will have a divergence half-angle of less than 90 degrees, a practical solution is achieved using non-imaging optics.
1. A method for designing a 3D non-imaging corner turner, said corner turner having an input port and an output port, and having an intended range of angles of output light rays comprising the steps of:
selecting an initial geometry for said 3D non-imaging corner turner such that every section of said corner turner in a plane parallel to the plane of the bend is approximately equivalent to an in-plane section of a 2D non-imaging corner turner; and
optimizing said corner turner, further comprising the steps of:
computing a merit function for said corner turner, said merit function comprising a measure of the fraction of optical power entering said input port which is delivered to said output port within said intended range of output ray angles;
adjusting the corner turner geometry based upon results of computing step; and
successively applying the computing and adjusting steps until an optimal non-imaging corner turner geometry is reached.
2. The method of claim 1 wherein said measure is a fraction of light rays entering said input port which are delivered to said output port within said intended range of output ray angles.