Granted Patent B2

US 12,228,756 · App. 17/416,381 · Granted Feb 18, 2025

Inventors: Oksana Shramkova (Liffré, FR); Valter Drazic (Betton, FR)

Assignee: InterDigital CE Patent Holdings, SAS

G02B5/1866G02B5/1814G02B27/0172G02B2027/0112G02B2027/0123G02B2027/0178

Abstract

Claims (367)

1. An eyewear apparatus, comprising:

at least one optical device,

wherein the optical device comprises:

a diffraction grating configured to diffract an incident light of a given wavelength on the optical device, the diffraction grating having a grating pitch above the given wavelength and being configured to diffract the incident light at a diffraction order having an absolute value equal to or greater than 2,

wherein the optical device comprises an optical waveguide configured to guide the light diffracted at a diffraction order having an absolute value equal to or greater than 2,

wherein the diffraction grating comprises a substrate of a first dielectric material with refractive index n 3 and at least one second dielectric material with refractive index n 2 on top of the substrate,

wherein the diffraction comprises a base pattern comprising the second dielectric material, the base pattern being configured to form a nanojet beam associated with edges of the base pattern from the light, and

wherein the base pattern comprises one block of the second dielectric material with refractive index n2 on top of the substrate, the block having a U-shape, the U-shape comprising two lobes with height H 2 and width W 2 separated by a central block with height H 1 , where H 1 lower is than H 2 , and

H

2

-

H

1

≥

W

2

tan

⁢

θ

B

⁢

1

′

with

θ

B

⁢

1

′

≈

θ

B

⁢

1

-

θ

i

2

,

θ i being the angle of the incident light with respect to a normal to the top surface of the diffraction grating and

θ

B

⁢

1

≈

90

⁢

°

-

sin

-

1

(

n

1

n

2

)

2

,

n 1 being the refractive index of a host medium in which the diffraction grating is placed.

2. The eyewear apparatus according to claim 1 , further comprising:

a light display engine configured to emit an image to display, and

optics configured to couple incoming light from the light display engine to the optical waveguide,

the optical waveguide being configured to guide incoming light towards an eye of a user to make the image visible to the user.

3. An optical device comprising:

a diffraction grating configured to diffract an incident light of a given wavelength on the optical device, the diffraction grating having a grating pitch above the given wavelength and being configured to diffract the incident light at a diffraction order having an absolute value equal to or greater than 2,

wherein the optical device comprises an optical waveguide configured to guide the light diffracted at a diffraction order having an absolute value equal to or greater than 2,

wherein the diffraction grating comprises a substrate of a first dielectric material with refractive index n 3 and at least one second dielectric material with refractive index n 2 on top of the substrate,

wherein the diffraction grating comprises a base pattern comprising the second dielectric material, the base pattern being configured to form a nanojet beam associated with edges of the base pattern from the light, and

wherein the base pattern comprises one block of the second dielectric material with refractive index n 2 on top of the substrate, the block having a U-shape, the U-share comprising two lobes with height H 2 and width W 2 separated by a central block with height H 1 , where H 1 lower is than H 2 , and

H

2

-

H

1

≥

W

2

tan

⁢

θ

B

⁢

1

′

with

θ

B

⁢

1

′

≈

θ

B

⁢

1

-

θ

i

2

,

θ

i

being the angle of the incident light with respect to a normal to the top surface of the diffraction grating and

θ

B

⁢

1

≈

9

⁢

0

∘

-

sin

-

1

(

n

1

n

2

)

2

,

n 1 being the refractive index of a host medium in which the diffraction grating is placed.

4. The optical device according to claim 3 , wherein the diffraction grating is configured to in-couple light incoming into the optical waveguide or for extracting light out of the optical waveguide.

5. The optical device according to claim 3 ,

wherein the diffraction grating is configured to in-couple light incoming into the optical waveguide, and

wherein the optical waveguide comprises another diffraction grating configured to extract light out of the optical waveguide, the other diffraction grating having a grating pitch above a wavelength of the light and the other diffraction grating being configured to diffract the light at a diffraction order having an absolute value equal to or greater than 2.

6. The optical device according to claim 3 ,

wherein W 1 being a width of the central block of the block having a U-shape, and W 2 being the width of each of the two lobes, and

wherein W 1 and W 2 depend on a grating pitch d of the diffraction grating with

W

1

<

d

3

⁢

and

⁢

W

1

+

W

2

≠

d

2

.

7. The optical device according to claim 3 ,

wherein base angles between a top surface of the U-shape and lateral surface of the U-shape are different from 90°, and

wherein n 2 =n 3 .

8. The optical device according to claim 3 , wherein n 3 <n 2 or n 3 =n 2 .

9. An optical device comprising:

a diffraction grating configured to diffract an incident light of a given wavelength on the optical device, the diffraction grating having a grating pitch above the given wavelength and being configured to diffract the incident light at a diffraction order having an absolute value equal to or greater than 2,

wherein the optical device comprises an optical waveguide configured to guide the light diffracted at a diffraction order having an absolute value equal to or greater than 2,

wherein the diffraction grating comprises a substrate of a first dielectric material with refractive index n 3 and at least one second dielectric material with refractive index n 2 on top of the substrate,

wherein the diffraction grating comprises a base pattern comprising the second dielectric material, the base pattern being configured to form a nanojet beam associated with edges of the base pattern from the light, and the base pattern comprises two blocks of the second dielectric material with refractive index n 2 having identical widths and heights, on top of the substrate, the two blocks being separated by a distance W 1 , the two blocks having a height H 2 with

H

2

≥

W

2

tan

⁢

θ

′

B

⁢

1

and

H

2

<

W

2

tan

⁢

θ

″

B

⁢

1

with W 2 being the width of each of the two blocks and θ′ B1 and θ″ B1 being respective angles of nanojet beam radiations associated with edges of the base pattern from the light, and

wherein

θ

B

⁢

1

′

≈

θ

B

⁢

1

-

θ

i

2

,

θ

B

⁢

1

″

≈

θ

B

⁢

1

+

θ

i

2

with θ i being the angle of the incident light with respect to a normal to the top surface of the diffraction grating and

θ

B

⁢

1

≈

9

⁢

0

∘

-

sin

-

1

(

n

1

n

2

)

2

,

n 1 being the refractive index of a host medium in which the diffraction grating is placed,

wherein W 1 being the distance separating the two blocks, and W 2 being the width of each of the two blocks, and

wherein W 1 and W 2 depend on a grating pitch d of the diffraction grating with

W

1

<

d

3

W

1

+

W

2

≠

d

2

.

10. The optical device according to claim 9 , wherein the diffraction grating is configured to in-couple light incoming into the optical waveguide or for extracting light out of the optical waveguide.

11. The optical device according to claim 9 ,

wherein the diffraction grating is configured to in-couple light incoming into the optical waveguide, and

wherein the optical waveguide comprises another diffraction grating configured to extract light out of the optical waveguide, the other diffraction grating having a grating pitch above a wavelength of the light and the other diffraction grating being configured to diffract the light at a diffraction order having an absolute value equal to or greater than 2.

12. The optical device according to claim 9 , wherein n 3 <n 2 or n 3 =n 2 .

13. An eyewear apparatus, comprising:

at least one optical device,

wherein the optical device comprises:

a diffraction grating configured to diffract an incident light of a given wavelength on the optical device, the diffraction grating having a grating pitch above the given wavelength and being configured to diffract the incident light at a diffraction order having an absolute value equal to or greater than 2,

wherein the optical device comprises an optical waveguide configured to guide the light diffracted at a diffraction order having an absolute value equal to or greater than 2,

wherein the diffraction grating comprises a substrate of a first dielectric material with refractive index n 3 and at least one second dielectric material with refractive index n 2 on top of the substrate,

wherein the diffraction grating comprises a base pattern comprising the second dielectric material, the base pattern being configured to form a nanojet beam associated with edges of the base pattern from the light, and the base pattern comprises two blocks of the second dielectric material with refractive index n 2 having identical widths and heights, on top of the substrate, the two blocks being separated by a distance W 1 , the two blocks having a height H 2 with

H

2

≥

W

2

tan

⁢

θ

B

⁢

1

′

and

H

2

<

W

2

tan

⁢

θ

B

⁢

1

″

with W 2 being the width of each of the two blocks and θ′ B1 and θ″ B1 being respective angles of nanojet beam radiations associated with edges of the base pattern from the light, and

wherein

θ

B

⁢

1

′

≈

θ

B

⁢

1

-

θ

i

2

,

θ

B

⁢

1

″

≈

θ

B

⁢

1

+

θ

i

2

with θ i being the angle of the incident light with respect to a normal to the top surface of the diffraction grating and

θ

B

⁢

1

≈

9

⁢

0

∘

-

sin

-

1

(

n

1

n

2

)

2

,

n 1 being the refractive index of a host medium in which the diffraction grating is placed,

wherein W 1 being the distance separating the two blocks, and W 2 being the width of each of the two blocks, and

wherein W 1 and W 2 depend on a grating pitch d of the diffraction grating with

W

1

<

d

3

and

W

1

+

W

2

≠

d

2

.

14. The eyewear apparatus according to claim 13 , further comprising:

a light display engine configured to emit an image to display, and

optics configured to couple incoming light from the light display engine to the optical waveguide,

the optical waveguide being configured to guide incoming light towards an eye of a user to make the image visible to the user.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (258)

Cited By (1)

US 12,326,562