Patent ID: 11199713

Abstract:
The present invention provides an apparatus (3) comprising a first out-coupling diffractive optical element (10) and a second out-coupling diffractive optical element (20). Each of the first and second out-coupling diffractive optical elements comprises a first region (12a, 22a) having a first repeated diffraction spacing, d1, and a second region (12b, 22b) adjacent to the first region having a second repeated diffraction spacing, d2, different from the first spacing, d1. The first region (12a) of the first out-coupling diffractive optical element (10) is superposed on and aligned with the second region (22b) of the second out-coupling diffractive optical element (20). The second region (12b) of the first out-coupling diffractive optical element (10) is superposed on and aligned with the first region (22a) of the second out-coupling diffractive optical element (20).