| CPC G02B 27/0172 (2013.01) [G02B 6/0026 (2013.01); G02B 6/0036 (2013.01); G02B 6/0065 (2013.01)] | 19 Claims |
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1. A display apparatus comprising:
a waveguide;
an input coupler on the waveguide, the input coupler being configured to introduce light corresponding to an image into the waveguide; and
an output coupler on the waveguide, the output coupler being configured to output light traveling within the waveguide to an outside of the waveguide,
wherein the output coupler comprises a plurality of first diffraction grating elements arranged apart from each other, the plurality of first diffraction grating elements being configured to diffract a first light portion in a first wavelength band among the light traveling within the waveguide, and
wherein a gap between adjacent first diffraction grating elements from among the plurality of first diffraction grating elements is greater than a width and a length of each of the plurality of first diffraction grating elements,
wherein the plurality of first diffraction grating elements is arranged such that a pitch between the adjacent first diffraction grating elements arranged in a center region of the output coupler is less than a pitch between the adjacent first diffraction grating elements arranged in a peripheral region of the output coupler.
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