Near-eye display waveguide device and near-eye display apparatus

1 . A near-eye display waveguide device, comprising m waveguide substrates stacked on each other, m being an integer and m>3, the near-eye display waveguide device receiving image-carrying light with an image field of view angle range, and the image-carrying light comprising light of less than m dominant wavelengths, wherein:

corresponding to each dominant wavelength, the m waveguide substrates are formed with at least two coupling-in gratings, the at least two coupling-in gratings are formed on different waveguide substrates and have different grating periods, for being used to couple light in different coupling-in field of view angle ranges into the corresponding waveguide substrates, wherein the coupling-in field of view angle ranges are each smaller than the image field of view angle range, and the coupling-in field of view angle ranges as a whole cover the image field of view angle range;

the m waveguide substrates are waveguide substrates W i , i is an integer and 1≤i'm, wherein,

for i=1, a coupling-in grating G (1,1) for a dominant wavelength λ 1 is formed on a waveguide substrate W 1 , and the coupling-in grating G (1,1) has a grating period d 1 ;

for i=m, a coupling-in grating G (m-1,2) for a dominant wavelength A m-1 is formed on a waveguide substrate W m , and the coupling-in grating G (m-1,2) has a grating period d m ; and

for 2≤i≤m−1, a coupling-in grating G (i,1) for a dominant wavelength A i and a coupling-in grating G (i−1,2) for the dominant wavelength λ i−1 are formed on the waveguide substrate W i , and satisfy: λ i -1>λ i >λ i+1 , wherein, for 2≤i≤m−1, the coupling-in grating G (i,1) and the coupling-in grating G (i-1,2) have different grating structure features, and the grating structure features comprise one or more of depth, height, duty cycle, blaze angle and optical coating of the gratings;

wherein, for 2≤i≤m−1, the coupling-in grating G (i,1) and the coupling-in grating G (i−1,2) have the same grating vector direction and grating period d i , and d i−1 >d i >d i+1 , and wherein, for 1≤i≤m−1: λ i /d i is approximately a constant C 1 , and/or A i /d i +1 is approximately a constant C 2 , wherein a deviation is within ±5%.

2 . The near-eye display waveguide device of claim 1 , wherein each waveguide substrate is formed with a coupling-out grating and at least one coupling-in grating;

after being coupled into a waveguide substrate through a corresponding coupling-in grating, the image-carrying light of each dominant wavelength propagates to the coupling-out grating of the waveguide substrate through a total reflection path corresponding to the coupling-in grating; and

the total reflection path corresponding to a coupling-in grating for coupling light of one dominant wavelength does not pass through a coupling-in grating for coupling light of another dominant wavelength.

3 . The near-eye display waveguide device of claim 1 , wherein the coupling-in gratings formed on the m waveguide substrates have the same grating vector direction; and

the coupling-in gratings formed on the m waveguide substrates for coupling light of different dominant wavelengths are separated from each other in a direction parallel to each waveguide substrate and perpendicular to the grating vector direction.

4 . The near-eye display waveguide device of claim 1 , wherein the projections of the at least two coupling-in gratings formed on different waveguide substrates for coupling light of the same dominant wavelength overlap each other in a direction perpendicular to the waveguide substrate.

5 . The near-eye display waveguide device of claim 4 , wherein at least two coupling-in gratings are formed on adjacent waveguide substrates.

6 . The near-eye display waveguide device of claim 1 , wherein m=4, and the image-carrying light comprises red, green, and blue light.

7 . The near-eye display waveguide device of claim 1 , wherein the m waveguide substrates are made of materials with the same or similar refractive index.

8 . The near-eye display waveguide device of claim 1 , wherein, for 1≤i≤m−1, j is an integer and 1≤j≤m−1, k=1 or 2, and i≠j, a coupling-in grating G (i,k) and a coupling-in grating G (j,k) are separated from each other in a direction perpendicular to the waveguide substrates.

9 . The near-eye display waveguide device of claim 1 , wherein, for 1≤i≤m−1, the projections of the coupling-in grating G (i,1) and the coupling-in grating G (i,2) overlap each other in a direction perpendicular to the waveguide substrates.

10 . The near-eye display waveguide device of claim 9 , wherein the coupling-in grating G (i,1) and the coupling-in grating G (i,2) are formed on adjacent waveguide substrates.

11 . A near-eye display apparatus, comprising the near-eye display waveguide device of claim 1 .

12 . The near-eye display apparatus of claim 11 , wherein the near-eye display device further comprises a lens and a frame for holding the lens close to eye, and the lens comprises the near-eye display waveguide device.