CN110231714B

CN110231714B - Method for enhancing light intensity uniformity of optical waveguide of AR glasses

Info

Publication number: CN110231714B
Application number: CN201910520564.0A
Authority: CN
Inventors: 张佳恒; 张卓鹏; 魏一振; 陈达如
Original assignee: Hangzhou Guangli Technology Co ltd
Current assignee: Hangzhou Guangli Technology Co ltd
Priority date: 2019-06-17
Filing date: 2019-06-17
Publication date: 2021-01-29
Anticipated expiration: 2039-06-17
Also published as: CN110231714A

Abstract

The invention relates to a method for enhancing light intensity uniformity of an optical waveguide of AR glasses. The method is characterized in that a special grating with a light splitting function is manufactured in a first reflecting area after light leaves a couple-in grating area according to light (without secondary energy loss) in an incident angle range from b to c. The special grating has partial diffraction effect on the light rays in the incident angle range (b to c), so that the reflection energy of the light rays in the incident angle range (b to c) in the optical waveguide substrate is reduced, the level that the energy is consistent with the light rays in the angle range (a to b) is reached, and the light intensity uniformity of the optical waveguide of the AR glasses is enhanced. The invention adopts the special grating, and has partial diffraction light effect on the light within the range of the incident angle, thereby controlling the light intensity of the partial light and enhancing the light intensity uniformity of the optical waveguide. The method has the advantages of simplicity, convenience, stability and the like.

Description

Method for enhancing light intensity uniformity of optical waveguide of AR glasses

Technical Field

The invention relates to the field of Augmented Reality (AR), in particular to a method for enhancing light intensity uniformity of an AR glasses optical waveguide.

Background

AR is a technology that combines real and virtual image, video, 3D model applications, the goal of which is to fit and interact with the real world around the virtual world on the screen. Commercial AR glasses are provided by companies such as Google and Microsoft, and the development and application of AR technology are led.

Optical waveguide-based AR glasses are one of the most promising AR glasses for mass application at present. The light waveguide structure is small, the weight is light, and the optical function is strong, so that the light AR glasses are core devices for realizing the light AR glasses. Currently, optical waveguides based on gratings (such as a cladding-in grating, a cladding-out grating, a folding grating, etc.) are the mainstream choice of AR glasses optical waveguides. However, the existing AR glasses optical waveguide has the defect of poor uniformity. Therefore, the method for enhancing the light intensity uniformity of the optical waveguide of the AR glasses has important significance for the application of the optical waveguide AR glasses.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a method for enhancing the light intensity uniformity of an optical waveguide of AR glasses.

The principle and the technical scheme of the invention are as follows:

functionally, the most basic structure of the optical waveguide of the AR glasses includes an optical waveguide substrate, a coupler-in grating, a coupler-out grating, and the like; light rays coming out of the micro display screen enter the manifold-in grating through the optical system, are then conducted through the optical waveguide substrate in a total reflection mode, are guided out through the manifold-out grating, and are emitted into human eyes to form images. One of the main reasons for poor light intensity uniformity of the AR glasses optical waveguide is that light with different incident angles has different light intensity losses due to different reflection times in the coupler-in grating region.

The incident angles of the light rays injected into the manifold-in grating are in one-to-one correspondence with the incident areas, so that the light rays in a certain incident angle range (a to b) can be determined to have secondary reflection in the manifold-in grating area, and accordingly the energy loss of the corresponding light rays is large, and the light rays in the other incident angle range (b to c) have no secondary reflection in the manifold-in grating area, so that no secondary energy loss exists.

The method for solving the problem is that a special grating with a light splitting function is manufactured in a first reflecting area after light leaves a couple-in grating area according to the light (without secondary energy loss) in an incident angle range (b-c). The special grating has partial diffraction effect on the light rays in the incident angle range (b to c), so that the reflection energy of the light rays in the incident angle range (b to c) in the optical waveguide substrate is reduced, the level that the energy is consistent with the light rays in the angle range (a to b) is reached, and the light intensity uniformity of the optical waveguide of the AR glasses is enhanced.

The method for realizing the enhancement of the light intensity uniformity of the optical waveguide of the AR glasses comprises the following steps: 1. the fact that the light rays in a certain incident angle range (a to b) have secondary reflection in the coupler-in grating area is obtained through detection or theoretical calculation, the light rays in the certain incident angle range (b to c) have no secondary reflection in the coupler-in grating area, and the light intensity loss ratio loss caused by the secondary reflection is obtained. 2. Calculating or measuring a first substrate reflection Area (AB) after the light rays in the incident angle range (b-c) leave the couple-in grating area; 3. and manufacturing a special grating in the Area (AB) of the optical waveguide substrate, wherein the special grating has partial diffraction light effect on light rays in an incident angle range (b to c) and ensures the light intensity loss ratio loss. The light intensity uniformity of the optical waveguide of the AR glasses can be enhanced after the steps.

The invention provides a method for enhancing light intensity uniformity of an optical waveguide of AR glasses, which adopts a special grating to have partial diffraction light effect on light rays within an incident angle range, thereby controlling the light intensity of the partial light rays and enhancing the light intensity uniformity of the optical waveguide. The method has the advantages of simplicity, convenience, stability and the like.

Drawings

Fig. 1 is a schematic diagram of an optical waveguide structure and an optical path of the AR glasses used in the present invention.

Detailed Description

As shown in fig. 1, the apparatus used in the present invention comprises: the grating 1 is an in-coupling grating, the optical waveguide substrate 2, the special grating 3 and the grating 4 is an out-coupling grating.

The method for specifically realizing the enhancement of the light intensity uniformity of the optical waveguide of the AR glasses comprises the following steps:

1. the method comprises the following steps of (1) obtaining that light rays in a certain incident angle range (a = 1.92-b = 1.57) have secondary reflection in a couple-in grating area through detection or theoretical calculation, wherein the unit of the angle is radian, namely 180 degrees corresponds to pi; light rays in a certain incidence angle range (b =1.57 to c = 1.40) have no secondary reflection in the couple-in grating region, and the light intensity loss ratio loss =0.1 due to the secondary reflection is obtained.

2. The first substrate reflection Area (AB) after the light rays of the incident angle range (b =1.57 to c = 1.40) leave the couple-in grating area is calculated or measured.

3. A special grating is formed in the Area (AB) of the optical waveguide substrate, and the special grating has partial diffraction effect on light rays in an incident angle range (b = 1.57-c = 1.40) and enables the loss ratio of light intensity to be about loss = 0.1. The light intensity uniformity of the optical waveguide of the AR glasses can be enhanced after the steps.

The above description is only an embodiment of the present invention, but the technical features of the present invention are not limited thereto, and any changes or modifications within the technical field of the present invention by those skilled in the art are covered by the claims of the present invention.

Claims

1. A method for enhancing light intensity uniformity of an optical waveguide of AR glasses comprises an optical waveguide substrate, an incoupling grating and an outcoupling grating; light coming out of the micro display screen enters the coupling grating through the optical system, then is conducted through total reflection of the optical waveguide substrate, is guided out through the coupling grating, and enters human eyes to form imaging, and the micro display screen is characterized in that:

step 1, detecting or calculating to obtain that light rays with a certain incidence angle range from a to b have secondary reflection in an incoupling grating region, light rays with a certain incidence angle range from b to c have no secondary reflection in the incoupling grating region, and obtaining a light intensity loss ratio loss caused by secondary reflection;

step 2, calculating or measuring a first substrate reflection area AB after the light rays in the range from the incident angle b to the incident angle c leave the coupled grating area;

and 3, manufacturing a grating on the area AB of the optical waveguide substrate, wherein the grating has partial diffraction light effect on the light in the range from the incident angle b to the incident angle c and ensures that the light intensity loss ratio is loss.