New design for geodesic lenses.

A new method of designing geodesic lenses is described. The lens shape is expressed with a uniform function. The curvature of the lens shape is restricted within an upper limit to prevent the light leaking from the waveguide. The value of the curvature limit can be specified at the start of design calculation. A comparison with a former design method is also given. The numerical aperture of the lens is found to be improved up to 24%.