| CPC G02B 6/0016 (2013.01) [G02B 5/1823 (2013.01); G02B 6/0036 (2013.01)] | 8 Claims |
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1. A light guide device, comprising a substrate and a first diffraction structure provided at the substrate, wherein:
the first diffraction structure comprises a first grating;
the first grating comprises a plurality of first grating units provided at intervals of a first period P1 along a first vector direction u1 and at intervals of a second period P2 along a second vector direction u2;
the first vector direction u1 is intersected with the second vector direction u2, the first period P1 is longer than the second period P2, forming unequal periods in two vector directions, and the first period P1 is at least 1.5 times the second period P2;
the light guide device further comprises a second diffraction structure provided at the substrate;
the second diffraction structure is configured for coupling incident light into the substrate;
the substrate is configured for totally reflecting the incident light from the second diffraction structure to the first diffraction structure;
the first diffraction structure is configured for coupling out light and is composed of the first grating, and the first grating is an improved one-dimensional grating with a period of P and a vector direction of u;
the first grating satisfies:
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PIC is a grating period of the second diffraction structure, uIC is a vector direction of the second diffraction structure, and PIC and uIC constitute grating vector information of the second diffraction structure.
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