Beam expander and method of operating the same

Patent metadata

Field	Value
Publication number	US-12019260-B2
Application number	US-202318136673-A
Country	US
Kind code	B2
Filing date	Apr 19, 2023
Priority date	Jul 22, 2020
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

A beam expander includes first and second optical elements spaced apart from each other, and a light diffuser having an angular aperture that diffuses incident light through the angular aperture, wherein the first optical element in-couples the diffused light such that light exiting the first optical element has a first cross-sectional shape and light having a second cross-sectional shape different from the first cross-sectional shape is incident on the second optical element, and the second optical element out-couples light incident from the first optical element.

First claim

What is claimed is:

1. A beam expander comprising:
a first optical element;
a second optical element spaced apart from the first optical element; and
a waveguide connecting the first optical element and the second optical element;
wherein the first optical element exits a light having a first cross-sectional shape, and
wherein the waveguide is configured to gradually transform the light having the first cross-sectional shape from the first optical element into light having a second cross-sectional shape different from and smaller than the first cross-sectional shape through total internal reflection, and to direct the transformed light to the second optical element.

2. The beam expander of claim 1 , further comprising:
a light diffuser diffusing incident light to in-couple the diffused light to the first optical element,
wherein an intensity of the light diffused by the light diffuser has a greater uniformity over a light cross section than an intensity of the incident light.

3. The beam expander of claim 2 , wherein the light diffuser outputs the incident light as a plurality of sub-lights that are spatially separated from each other.

4. The beam expander of claim 2 , wherein the light diffuser modulates a phase of the incident light and outputs the incident light as a plurality of sub-lights.

5. The beam expander of claim 2 , wherein the light diffuser performs spatial non-uniformity phase modulation on the incident light and outputs a plurality of sub-lights.

6. The beam expander of claim 2 , wherein the light diffuser comprises at least one of a microlens raster, a phase mask, a matte diffuser, a diffractive optical element, and a holographic optical element.

7. The beam expander of claim 2 , wherein the incident light has an optical cross-sectional profile of at least one of a Gaussian beam, a multimode beam, a cylindrical beam, a super-Gaussian beam, and a Laguerre-Gaussian beam.

8. The beam expander of claim 2 , wherein the light diffuser and the first optical element are arranged to overlap each other in a direction perpendicular to a length direction of the waveguide.

9. The beam expander of claim 2 ,
wherein the light diffuser is arranged on a first surface of the waveguide, and
wherein the first optical element is arranged on a second surface opposite to the first surface of the waveguide.

10. The beam expander of claim 2 , wherein the light diffuser is integrated with the first optical element.

11. The beam expander of claim 2 , wherein a uniformity of an intensity of the light out-coupled by the second optical element is greater than a uniformity of an intensity of the light incident on the light diffuser.

12. The beam expander of claim 1 , wherein the second cross-sectional shape is a polygonal shape.

13. The beam expander of claim 1 , wherein the first cross-sectional shape is a circle or an ellipse.

14. The beam expander of claim 1 , wherein at least one of the first optical element and the second optical element comprises at least one of a diffractive optical element and a holographic optical element.

15. The beam expander of claim 1 , further comprising a laser diode that provides light.

16. The beam expander of claim 1 , wherein the second optical element collimates, at a divergence or convergence angle of less than 0.25°, light incident on the second optical element.

17. An electronic apparatus comprising:
a light source providing a light;
a first optical element in-coupling the light to exit a light having a first cross-sectional shape by using the in-coupled light;
a second optical element spaced apart from the first optical element; and
a waveguide connecting the first optical element and the second optical element,
wherein the waveguide is configured to gradually transform the light having the first cross-sectional shape from the first optical element into light having a second cross-sectional shape different from and smaller than the first cross-sectional shape through total internal reflection, and to direct the transformed light to the second optical element.

18. The electronic apparatus of claim 17 , further comprising:
a light diffuser diffusing the light provided from the light source to in-couple the diffused light to the first optical element.

19. The electronic apparatus of claim 17 , wherein the second optical element out-couples the transformed light to illuminate one of a redirector, a screen, a liquid crystal display (LCD) panel, or imaging matrices.

20. The electronic apparatus of claim 17 , wherein the electronic apparatus is one of a helmet-mounted display device, an indicator on a vehicle windshield, and a fingerprint scanner.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Morozov Aleksander V
• Putilin Andrey N
• Dubynin Sergey E
• Choi Chilsung
• Dubinin German B
• Lee Hongseok
• Song Hoon

Classifications

• G02B27/425

  in illumination systems (mask illumination systems in photolithographic systems G03F7/70158) · CPC title

• G02B27/0944 Primary

  Diffractive optical elements, e.g. gratings, holograms (gratings per se G02B5/18; holograms used as optical elements per se G02B5/32) · CPC title

• G02B5/32

  Holograms used as optical elements · CPC title

• G02B30/50

  the image being built up from image elements distributed over a three-dimensional [3D] volume, e.g. voxels · CPC title

• G02B27/4272

  having plural diffractive elements positioned sequentially along the optical path · CPC title