Optical device

Patent metadata

Field	Value
Publication number	US-12228756-B2
Application number	US-201917416381-A
Country	US
Kind code	B2
Filing date	Dec 20, 2019
Priority date	Dec 21, 2018
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

An optical device and an eyeware apparatus comprising the optical device are disclosed. The optical device comprises a diffraction grating configured to diffract an incident light of a given wavelength on said optical device, said diffraction grating having a grating pitch above said given wavelength and being configured to diffract said 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 for guiding said light diffracted at a diffraction order having an absolute value equal to or greater than 2. 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 deposited on said substrate, where n 3 <n 2 or n 3 =n 2 .

First claim

The invention claimed is:

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

Assignees

• Interdigital Ce Patent Holdings Sas

Inventors

• Shramkova Oksana
• Drazic Valter

Classifications

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G02B2027/0123

  comprising devices increasing the field of view · CPC title

• G02B2027/0112

  comprising device for genereting colour display · CPC title

• G02B27/0172

  characterised by optical features · CPC title

• G02B5/1814

  structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings (G02B5/189 takes precedence) · CPC title