CPC G02B 26/0875 (2013.01) [B42D 25/30 (2014.10); B42D 25/405 (2014.10); G02B 1/10 (2013.01); G02B 27/18 (2013.01); G03F 1/68 (2013.01)] | 15 Claims |
1. An optical element comprising a caustic layer made of a piece of reflective, or refractive transparent or partially transparent, first optical material, and having a light-redirecting surface with a relief pattern,
wherein
the optical element includes a mask layer disposed, respectively, on an optical surface of the optical element or within the optical element, the mask layer comprising a mask pattern and having a variable light transmission coefficient, the mask layer being adapted to at least partially transmit incoming light upon illumination of the optical element with a point-like light source; and
the relief pattern of the light-redirecting surface of the caustic layer is configured to redirect incident light received by the optical element from the point-like light source and form a projected image containing a visible caustic pattern reproducing a reference pattern, wherein
the point-like light source is a source of light whose angular size is sufficiently small that light can be considered to arise from a single point.
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