Display apparatus for providing expanded viewing window

1 . A display apparatus comprising:

a light guide plate comprising an input coupler and an output coupler; and

an image providing apparatus configured to provide a plurality of images traveling in different directions to the input coupler,

wherein the image providing apparatus comprises:

a spatial light modulator facing the input coupler and comprising a plurality of display regions configured to provide the plurality of images to the input coupler; and

a light source configured to provide coherent illumination light to the spatial light modulator,

wherein the spatial light modulator is provided such that each display region of the plurality of display regions is configured to provide a respective image to the input coupler, each respective image being formed by a different respective diffraction order,

wherein the input coupler comprises a first sub input coupler, a second sub input coupler, and a third sub input coupler configured to propagate an image provided from the image providing apparatus at different angles in the light guide plate,

wherein the plurality of display regions of the spatial light modulator comprises a first display region, a second display region, and a third display region corresponding to the first sub input coupler, the second sub input coupler, and the third sub input coupler, respectively, and

wherein the first display region is configured such that a first image is obliquely incident on the first sub input coupler from the first display region, the second display region is configured such that a second image is perpendicularly incident on the second sub input coupler from the second display region, and the third display region is configured such that a third image is obliquely incident on the third sub input coupler.

2 . The display apparatus of claim 1 , wherein a size of the spatial light modulator is larger than a size of the input coupler.

3 . The display apparatus of claim 1 , wherein the plurality of display regions of the spatial light modulator comprises the first display region configured to provide the first image formed by a −1st order diffraction of the coherent illumination light to the input coupler, the second display region configured to provide the second image formed by a 0th order diffraction of the coherent illumination light to the input coupler, and the third display region configured to provide the third image formed by a +1st order diffraction of the coherent illumination light to the input coupler.

4 . The display apparatus of claim 3 , wherein the spatial light modulator is provided such that a center of the second display region is aligned with a center of the input coupler.

5 . The display apparatus of claim 3 , wherein the input coupler is configured such that the first image, the second image, and the third image, which are incident on the input coupler at different angles, propagate in the light guide plate at different angles.

6 . The display apparatus of claim 5 , wherein the output coupler is configured such that the first image, the second image, and the third image are emitted at different angles through the output coupler.

7 . The display apparatus of claim 1 , wherein the plurality of display regions respectively correspond to a plurality of sub input couplers.

8 . The display apparatus of claim 7 , wherein the first sub input coupler is configured to receive the first image that is −1st order diffracted by the first display region, the second sub input coupler is configured to receive the second image that is 0th order diffracted by the second display region, and the third sub input coupler is configured to receive the third image that is +1st order diffracted by the third display region.

9 . The display apparatus of claim 8 , wherein a size of the first display region is greater than a size of the first sub input coupler, a size of the second display region is greater than a size of the second sub input coupler, and a size of the third display region is greater than a size of the third sub input coupler.

10 . The display apparatus of claim 8 , wherein the first sub input coupler is configured to incline a direction of the first image by a first angle to provide the first image to the light guide plate, the second sub input coupler is configured to incline a direction of the second image by a second angle different from the first angle to provide the second image to the light guide plate, and the third sub input coupler is configured to incline a direction of the third image by a third angle different from the first angle and the second angle to provide the third image to the light guide plate.

11 . The display apparatus of claim 8 , wherein the output coupler is configured such that the first image, the second image, and the third image are emitted at different angles through the output coupler.