| CPC G02B 27/0172 (2013.01) [G02B 27/0179 (2013.01); G02B 27/4205 (2013.01); G02B 27/44 (2013.01); G02B 27/0093 (2013.01); G02B 2027/0178 (2013.01); G02B 2027/0187 (2013.01)] | 18 Claims |

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1. An optical waveguide element, comprising:
an optical waveguide layer;
a first grating, overlapping with the optical waveguide layer and comprising at least one first sub-grating unit;
wherein the at least one first sub-grating unit is configured to be switchable between a diffraction state and a non-diffraction state, and the at least one first sub-grating unit in a diffraction state guides incident light in the optical waveguide layer out of the optical waveguide layer for display,
a plurality of first sub-grating units are provided, each of the plurality of first sub-grating units comprises a first control electrode to control a state of the first sub-grating unit, and the first control electrodes of at least two of the plurality of first sub-grating units are independent of each other, wherein
a diffraction efficiency of the plurality of first sub-grating units are set to be gradually increased along a propagation direction of light in the optical waveguide layer.
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