A device configured to enlarge an exit pupil area of a visual optical apparatus, the device comprising: a diffraction grating configured to output a plurality of diffracted light beams of a plurality of diffraction orders by diffracting an incident light beam; and a waveguide provided on the diffraction grating, the waveguide being configured to form an exit pupil based on a first diffracted light beam among the plurality of diffracted light beams output from the diffraction grating and to form exit pupil orders based on a second diffracted light beam among the plurality of diffracted light beams output from the diffraction grating; wherein the first diffracted light beam comprises a 0 order diffracted light beam, and wherein the second diffracted light beam comprises a +1 order diffracted light beam and a -1 order diffracted light beam, wherein the waveguide is further configured to: form a first exit pupil order adjacent to the exit pupil based on the +1 order diffracted light beam, and form a second exit pupil order adjacent to the exit pupil and opposite the first exit pupil order based on the -1 order diffracted light beam; characterized in that the waveguide is further configured to form the first exit pupil order by totally internally reflecting once the +1 order diffracted light beam output from the diffraction grating and then outputting a portion of the +1 order diffracted light beam, and to form the second exit pupil order by totally internally reflecting once the -1 order diffracted light beam output from the diffraction grating and then outputting a portion of the -1 order diffracted light beam. a diffraction grating configured to output a plurality of diffracted light beams of a plurality of diffraction orders by diffracting an incident light beam; and a waveguide provided on the diffraction grating, the waveguide being configured to form an exit pupil based on a first diffracted light beam among the plurality of diffracted light beams output from the diffraction grating and to form exit pupil orders based on a second diffracted light beam among the plurality of diffracted light beams output from the diffraction grating; wherein the first diffracted light beam comprises a 0 order diffracted light beam, and wherein the second diffracted light beam comprises a +1 order diffracted light beam and a -1 order diffracted light beam, wherein the waveguide is further configured to: form a first exit pupil order adjacent to the exit pupil based on the +1 order diffracted light beam, and form a second exit pupil order adjacent to the exit pupil and opposite the first exit pupil order based on the -1 order diffracted light beam; characterized in that the waveguide is further configured to form the first exit pupil order by totally internally reflecting once the +1 order diffracted light beam output from the diffraction grating and then outputting a portion of the +1 order diffracted light beam, and to form the second exit pupil order by totally internally reflecting once the -1 order diffracted light beam output from the diffraction grating and then outputting a portion of the -1 order diffracted light beam. form a first exit pupil order adjacent to the exit pupil based on the +1 order diffracted light beam, and form a second exit pupil order adjacent to the exit pupil and opposite the first exit pupil order based on the -1 order diffracted light beam; characterized in that the waveguide is further configured to form the first exit pupil order by totally internally reflecting once the +1 order diffracted light beam output from the diffraction grating and then outputting a portion of the +1 order diffracted light beam, and to form the second exit pupil order by totally internally reflecting once the -1 order diffracted light beam output from the diffraction grating and then outputting a portion of the -1 order diffracted light beam.