Beam Combining Device

Patent metadata

Field	Value
Publication number	US-2016299347-A1
Application number	US-201615185947-A
Country	US
Kind code	A1
Filing date	Jun 17, 2016
Priority date	Dec 20, 2013
Publication date	Oct 13, 2016
Grant date	—

Abstract

The present application discloses a beam combining device, which includes a reflective diffractive grating surface configured to combine a first, a second and a third incident light beam having different colors to a single diffracted mixed-color light beam when impinging on the reflective diffractive grating surface, wherein a profile of the grating surface is configured according to an optimization criterion with respect to a diffraction efficiency.

First claim

What is claimed is:

1 . A beam combining device, comprising:
a reflective diffractive grating surface configured to combine a first incident light beam, a second incident light beam and a third incident light beam into a single diffracted mixed-color light beam when impinging on the reflective diffractive grating surface, wherein the first incident light beam, the second incident light beam, and the third light beam are different colors, wherein a profile of the grating surface is configured according to an optimization criterion with respect to a diffraction efficiency.

2 . The beam combining device of claim 1 , wherein the reflective diffractive grating surface comprises a blazed grating.

3 . The beam combining device of claim 2 , wherein the blazed grating comprises grooves having an asymmetric triangular form.

4 . The beam combining device of claim 1 , wherein the reflective diffractive grating surface comprises a sub-wavelength grating.

5 . The beam combining device of claim 4 , wherein the sub-wavelength grating comprises grooves arranged on the grating surface with a period of less than a wavelength of one of the first incident light beam, the second incident light beam, or the third incident light beam.

6 . The beam combining device of claim 5 , wherein the grooves of the sub-wavelength grating have a symmetric triangular form.

7 . The beam combining device of claim 5 , wherein the grooves of the sub-wavelength grating have a sinusoidal form.

8 . The beam combining device of claim 1 , wherein the grating surface comprises a reflective metal layer covering the grating surface.

9 . The beam combining device of claim 1 , wherein the profile of the grating surface is concave.

10 . The beam combining device of claim 1 , wherein the optimization criterion is based on at least one of angles of the first incident light beam, the second incident light beam, and the third incident light beam to a normal, an angle of the diffracted light beam to normal, wavelengths of the first incident light beam, the second incident light beam, and the third incident light beam, a diffractive order number, and a grating period of the grating surface.

11 . The beam combining device of claim 10 , wherein the optimization criterion is based on the relation:

sin




θ
i

+

sin




θ
w

=

m




λ
i

T

,

wherein θ i denotes an angle of an i-th incident light beam to normal, wherein i is a positive integer, wherein θ w denotes an angle of a diffracted light beam to a normal, wherein λ i denotes the wavelength of the i-th incident light beam, wherein m denotes the diffractive order number; and wherein T denotes the grating period of the grating surface.

12 . The beam combining device of claim 11 , wherein the diffractive order number (m) is equal to negative one.

13 . The beam combining device of claim 10 , wherein the grating period of the grating surface is approximately 2500 lines per millimeter.

14 . The beam combining device of claim 10 , wherein the wavelengths of the first incident light beam, the second incident light beam, and the third incident light beam correspond to wavelengths of a red laser light, a green laser light and blue laser light.

15 . A laser scan pico-projector, comprising:
a first laser configured to generate a first incident light beam; a second laser configured to generate a second incident light beam; and a third laser configured to generate a third incident light beam, wherein the first incident light beam, the second incident light beam, and the third incident light beam are different colors, and wherein the first laser, the second laser, and the third laser are arranged such that the first incident light beam, the second incident light beam, and the third incident light beam are directed to a reflective diffractive grating surface of a beam combining device.

16 . A method for generating a mixed-color light beam based on a combination of a first incident light beam, a second incident light beam and a third incident light beam, the method comprising:
arranging the first incident light beam, the second incident light beam, and the third incident light beam with respect to a reflective diffractive grating surface of a beam combining device, according to the relation:

θ
i

=

arcsin


(

m




λ
i

T

-

sin




θ
w

)

,

wherein θ i denotes an angle of an i-th incident light beam to normal, wherein i is a positive integer, wherein θ w denotes an angle of a mixed-color light beam to a normal, wherein λ i denotes a wavelength of the i-th incident light beam, wherein m denotes a diffractive order number, and wherein T denotes a grating period of the grating surface.

Assignees

• Huawei Tech Co Ltd

Inventors

• Petrov Nikolay Ivanovich
• Storozheva Angela Liudvigovna
• Khromov Maksim Nikolaevich
• Sokolov Yury Mihaylovitch
• Nikitin Vladislav Gennadievich

Classifications

• G02B27/1086 Primary

  operating by diffraction only · CPC title

• G02B27/104 Primary

  for use with scanning systems (scanning systems G02B26/10) · CPC title

• G03B33/06

  by additive-colour projection apparatus · CPC title

• G02B27/14

  operating by reflection only · CPC title

• G02B26/101

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title