CN112630883A

CN112630883A - Optical waveguide structure

Info

Publication number: CN112630883A
Application number: CN202011609719.7A
Authority: CN
Inventors: 高一峰; 熊羚鹤; 孙理斌; 汪杰; 陈远
Original assignee: Ningbo Sunny Olai Technology Co ltd
Current assignee: Ningbo Sunny Olai Technology Co ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-04-09

Abstract

The invention provides an optical waveguide structure. The optical waveguide structure includes: an optical waveguide sheet; the coupling-in gratings are arranged on the optical waveguide sheet and couple light emitted by an external image source into the optical waveguide sheet; the grating coupling-in device comprises a turning grating, a plurality of coupling gratings and a plurality of coupling gratings, wherein the turning grating is used for receiving light coupled into the grating, and the plurality of coupling gratings are arranged at intervals around the circumference of the turning grating; the coupling-out grating is used for receiving the light of the turning grating; the detectors are respectively positioned on one side of the coupled gratings, which is far away from the turning grating, and are used for receiving light which does not enter the turning grating in the coupled gratings. The invention solves the problem that the optical waveguide structure in the prior art is difficult to realize real-time detection.

Description

Optical waveguide structure

Technical Field

The invention relates to the technical field of diffraction optical equipment, in particular to an optical waveguide structure.

Background

With continuous innovation of future technologies, Virtual Reality (VR), Augmented Reality (AR), Mixed Reality (MR) have gradually entered industries such as industry, education, wherein in the aspect of AR augmented reality, optical waveguide technology is an indispensable part, for the display effect is more excellent, the concatenation scheme of various complex designs has appeared, but it is a big problem to carry out real-time detection to the image of ray apparatus at present, in case the ray apparatus image has appeared the concatenation deviation, can greatly influence user experience.

That is, the optical waveguide structure in the prior art has a problem that real-time detection is difficult to achieve.

Disclosure of Invention

The invention mainly aims to provide an optical waveguide structure to solve the problem that real-time detection is difficult to realize in the optical waveguide structure in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided an optical waveguide structure comprising: an optical waveguide sheet; the coupling-in gratings are arranged on the optical waveguide sheet and couple light emitted by an external image source into the optical waveguide sheet; the grating coupling-in device comprises a turning grating, a plurality of coupling gratings and a plurality of coupling gratings, wherein the turning grating is used for receiving light coupled into the grating, and the plurality of coupling gratings are arranged at intervals around the circumference of the turning grating; the coupling-out grating is used for receiving the light of the turning grating; the detectors are respectively positioned on one side of the coupled gratings, which is far away from the turning grating, and are used for receiving light which does not enter the turning grating in the coupled gratings.

Furthermore, the detector and the optical waveguide sheet are arranged at intervals, the optical waveguide structure further comprises a plurality of slit gratings, the slit gratings are arranged on the optical waveguide sheet and are arranged in one-to-one correspondence with the detector, and the slit gratings are located in the light incidence direction of the detector.

Further, the detector is located on the light incident side of the optical waveguide sheet.

Furthermore, the detectors are arranged on the optical waveguide sheet and the two detectors are respectively positioned on two opposite side surfaces of the optical waveguide sheet.

Furthermore, the coupling-in grating, the turning grating and the coupling-out grating are all positioned on the same side surface of the optical waveguide sheet; or the coupling-in grating and the turning grating are positioned on the same side surface of the optical waveguide sheet, and the coupling-out grating and the turning grating are positioned on two opposite side surfaces of the optical waveguide sheet.

Furthermore, when the coupling-out grating and the turning grating are positioned on two opposite side surfaces of the optical waveguide sheet, the turning grating is a two-dimensional grating, and the coupling-out grating is a one-dimensional grating.

Further, the incoupling grating is a diffraction grating.

Further, the period of the diffraction grating is equal to or greater than 300 nanometers and equal to or less than 600 nanometers.

Furthermore, the material of the optical waveguide sheet is glass; and/or the thickness of the optical waveguide sheet is not less than 400 micrometers and not more than 1 millimeter; and/or the coupling-out grating is one of a blazed grating, an inclined grating and a rectangular grating; and/or the detector is a CMOS detector.

Furthermore, the number of the coupling-in gratings is two, the two coupling-in gratings are respectively positioned at two opposite sides of the turning grating, the connecting line of the center of the coupling-in grating and the center of the turning grating is vertical to the connecting line of the center of the coupling-out grating and the center of the turning grating, and the coupling-out grating couples light out of the optical waveguide sheet.

The optical waveguide structure comprises an optical waveguide sheet, a plurality of coupling-in gratings, a turning grating, a coupling-out grating and a detector, wherein the coupling-in grating is arranged on the optical waveguide sheet and couples light emitted by an external image source into the optical waveguide sheet; the turning grating is used for receiving light coupled into the grating, and a plurality of coupled-in gratings are arranged at intervals around the circumference of the turning grating; the coupling grating is used for receiving the light of the turning grating; the detectors are respectively positioned at one side of the coupled gratings far away from the turning grating and used for receiving light which does not enter the turning grating in the coupled gratings.

The coupling grating is arranged on the optical waveguide sheet, so that most of light emitted by an external image source can be coupled into the optical waveguide sheet, and the coupling efficiency of the optical waveguide sheet is ensured. The arrangement of the coupling-in gratings can couple light emitted by an external image source into the optical waveguide sheet from two directions, and is favorable for improving the output efficiency of the optical waveguide structure. The turning grating is positioned on one side of the coupling grating, so that most of the light coupled into the grating can be transmitted into the turning grating for amplifying the light by the turning grating, and the stable work of the turning grating is ensured. The detectors are arranged on one sides of the coupled gratings far away from the turning grating, so that the detectors can judge whether the images of the external image sources are synchronous or not and whether the images deviate or not by analyzing the comparison of the positions and the strengths of the light intensity signals received by the detectors and the originally set standard value by utilizing the light which is not coupled into the turning grating. Once the abnormal image is found, the imaging can be calibrated in real time through the position adjustment of the external image source, and the application provides a convenient calibration method to ensure the accuracy of the output images of the two image sources.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic structural view of an optical waveguide structure according to a first embodiment of the present invention; and

fig. 2 is a schematic structural view showing an optical waveguide structure according to a second embodiment of the present invention;

fig. 3 is a schematic structural view showing an optical waveguide structure according to a third embodiment of the present invention;

FIG. 4 is a schematic diagram showing a front structure of the optical waveguide sheet of FIG. 3;

FIG. 5 is a schematic view showing a reverse structure of the optical waveguide sheet of FIG. 3;

fig. 6 is a schematic view showing a propagation path of light in the optical waveguide sheet of fig. 3.

Wherein the figures include the following reference numerals:

10. an optical waveguide sheet; 20. coupling in a grating; 30. turning the grating; 40. coupling out the grating; 50. a detector; 60. a slit grating.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

It is noted that, unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

In the present invention, unless specified to the contrary, use of the terms of orientation such as "upper, lower, top, bottom" or the like, generally refer to the orientation as shown in the drawings, or to the component itself in a vertical, perpendicular, or gravitational orientation; likewise, for ease of understanding and description, "inner and outer" refer to the inner and outer relative to the profile of the components themselves, but the above directional words are not intended to limit the invention.

The invention provides an optical waveguide structure, aiming at solving the problem that the real-time detection of the optical waveguide structure in the prior art is difficult to realize.

As shown in fig. 1 to 6, the optical waveguide structure includes an optical waveguide sheet 10, a plurality of incoupling gratings 20, a turning grating 30, an outcoupling grating 40 and a detector 50, the incoupling gratings 20 are disposed on the optical waveguide sheet 10, and the incoupling gratings 20 couple light emitted from an external image source into the optical waveguide sheet 10; the turning grating 30 is used for receiving the light coupled into the grating 20, and a plurality of coupling gratings 20 are arranged at intervals around the turning grating 30; the outcoupling grating 40 is used for receiving the light of the turning grating 30; the detectors 50 are respectively disposed on a side of the coupled gratings 20 away from the turning grating 30, and are used for receiving light that does not enter the turning grating 30 in the coupled gratings 20.

By disposing the incoupling grating 20 on the optical waveguide sheet 10, the light emitted from an external image source can be mostly incoupled into the optical waveguide sheet 10, ensuring the incoupling efficiency of the optical waveguide sheet 10. The arrangement of the plurality of coupling-in gratings 20 can couple light emitted from an external image source into the optical waveguide sheet 10 from two directions, which is advantageous to improve the output efficiency of the optical waveguide structure. The turning grating 30 is located at one side of the incoupling grating 20, and is configured such that most of the light coupled into the turning grating 20 can be incident into the turning grating 30 for amplifying the light by the turning grating 30, thereby ensuring that the turning grating 30 can operate stably. The detectors 50 are disposed on the sides of the coupled gratings 20 far away from the turning grating 30, so that the detectors 50 can determine whether the images of the external image sources are synchronous or not and whether the images are shifted or not by analyzing the comparison between the positions and intensities of the light intensity signals received by the detectors 50 and the originally set standard values by using the light which is not coupled into the turning grating 30. The imaging is calibrated by adjusting the position of the external image source, and the application provides a convenient calibration method to ensure the accuracy of the output images of the two image sources.

It should be noted that the turning grating 30 and the coupling-out grating 40 are both disposed on the optical waveguide sheet 10, so that the turning grating 30 receives the light coupled into the grating 20, and so that the coupling-out grating 40 receives the light coupled into the turning grating 30. The incoupling grating 20 couples light into the optical waveguide sheet, the outcoupling grating 40 couples light in the optical waveguide sheet out to the external environment, and the turning grating 30 couples light coupled at the incoupling grating 20 into the outcoupling grating 40.

Since not all the light coupled into the coupling grating 20 is coupled into the turning grating 30, the detector 50 disposed at a position of the coupling grating 20 away from the turning grating 30 can receive the light which is not used for imaging by the coupling grating 20, so as to detect whether the images of the external image sources are synchronous or not and whether the images are shifted according to the light which is not used for imaging by the coupling grating 20, and the imaging of the optical waveguide structure is not affected.

It should be noted that the turning grating 30 and the coupling grating 40 can be designed separately or integrally. As light propagates within the optical waveguide sheet 10, the optical waveguide sheet 10 expands the received light at least in one dimension so that the light propagates at least toward one direction. The detector 50 described above is used to detect the intensity of the light field inside the optical waveguide sheet 10, which affects the quality of the image that eventually enters the human field of view. On the basis, a standard reference quantity of the light field intensity can be set, and if the light field intensity is detected to be lower than the reference quantity, the energy can be timely increased at the light source to enhance the light field intensity entering the optical waveguide sheet 10; if the detected value is higher than the reference value, the light source is adjusted to reduce the intensity. Therefore, the optical field in the optical waveguide sheet 10 can be detected in real time and compensated and adjusted in time according to the detection result, and the imaging quality of the optical waveguide sheet 10 is ensured.

The position and the intensity of the light intensity signals on the detectors 50 are analyzed to judge which position the grating works abnormally through the detection of the light which is not used for imaging by the detectors 50, so that the image influence generated by the defect is pre-compensated through the adjustment of an image source, and the imaging quality is ensured.

Example one

As shown in fig. 1, the detector 50 and the optical waveguide sheet 10 are arranged at intervals, the optical waveguide structure further includes a plurality of slit gratings 60, the slit gratings 60 are arranged on the optical waveguide sheet 10, the slit gratings 60 and the detectors 50 are arranged in a one-to-one correspondence, and the slit gratings 60 are located in the light incident direction of the detector 50. The slit grating 60 is arranged on the optical waveguide sheet 10, the slit gratings 60 are arranged in one-to-one correspondence with the detectors 50, and the slit gratings 60 are located in the light incident direction of the detectors 50, so that most of the light coupled into the grating 20 and not entering the bend grating 30 can be incident into the slit gratings 60 and coupled out from the slit gratings 60 to the detectors 50 in one-to-one correspondence, which is convenient for the detectors 50 to detect the light field inside the optical waveguide sheet 10 in real time and compensate and adjust in time according to the detection result, thereby ensuring the imaging quality of the optical waveguide sheet 10.

Specifically, the detector 50 is located on the light incident side of the optical waveguide sheet 10. Since the slit grating 60 and the incoupling grating 20 are on the same side surface of the optical waveguide sheet 10, the light outcoupled from the slit grating 60 can be directed to the light incident side of the optical waveguide sheet 10, so as to ensure that the detector 50 stably receives the light outcoupled from the slit grating 60.

In the embodiment shown in fig. 1, the in-coupling grating 20, the turning grating 30 and the out-coupling grating 40 are located on the same side of the optical waveguide sheet 10. The arrangement is such that the light-entrance side and the light-exit side of the optical waveguide structure are located on the same side of the optical waveguide sheet 10, so as to facilitate application of the optical waveguide structure in a small space.

In particular, the incoupling grating 20 is a diffraction grating. The coupling grating 20 is a diffraction grating, so that the total reflection of light emitted by an external image source in the diffraction grating can be ensured, most of the light emitted by the external image source can be coupled into the optical waveguide sheet 10, and the coupling efficiency of the coupling grating 20 is ensured.

Specifically, the period of the diffraction grating is 300 nm or more and 600 nm or less. The period of the diffraction grating is limited within the range of 300 nm to 600 nm, so that the light emitted by an external image source can be totally reflected in the diffraction grating, most of the light emitted by the external image source can be coupled into the optical waveguide sheet 10, and the coupled grating 20 can stably work.

The material of the optical waveguide sheet 10 is glass. The optical waveguide sheet 10 is made of glass, which is advantageous for transmitting light inside the optical waveguide sheet 10 and reduces the production cost of the optical waveguide sheet 10. The glass is a high refractive index glass, which effectively increases the angle of view of the optical waveguide sheet 10 and improves the image quality of the optical waveguide sheet 10. Similarly, the optical waveguide sheet 10 of different materials may be selected according to actual requirements.

Alternatively, the thickness of the optical waveguide sheet 10 is 400 μm or more and 1 mm or less. If the thickness of the optical waveguide sheet 10 is less than 400 μm, the optical waveguide sheet 10 is not easy to manufacture, the processing difficulty of the optical waveguide sheet 10 is increased, and the optical waveguide sheet 10 is easily broken during use, thereby reducing the structural strength of the optical waveguide sheet 10. If the thickness of the optical waveguide sheet 10 is larger than 1 mm, the thickness of the optical waveguide sheet 10 becomes too large, which is disadvantageous for miniaturization of the optical waveguide sheet 10. The thickness of the optical waveguide sheet 10 is limited to the range of 400 μm to 1 mm, and the structural strength of the optical waveguide sheet 10 is ensured while the miniaturization of the optical waveguide sheet 10 is ensured.

Optionally, the outcoupling grating 40 is one of a blazed grating, a slanted grating, a rectangular grating. The coupling-out grating 40 is one of a blazed grating, an inclined grating and a rectangular grating, different gratings can be adopted according to different application requirements due to the arrangement, the grating can couple out light field information, specific parameters can be adjusted, the uniformity of the coupled-out light field is adjusted to meet different application requirements, and the universality of the optical waveguide sheet 10 is enhanced while the coupling-out grating 40 can couple out imaging light to human eyes.

The blazed grating is a grating having a blazed characteristic, in which the groove surface is not parallel to the normal of the grating, that is, a small included angle exists between the groove surface and the normal of the grating. The sawtooth type grating is an ideal blazed grating, and the cross section of the sawtooth type grating is in a sawtooth structure for diffraction. The tilted grating is a grating in which the plane of the grating and the tangential direction of the grating form a certain inclination angle. The rectangular grating is a grating which diffracts light with a rectangular cross section.

In particular, detector 50 is a CMOS detector. The detector 50 is a CMOS detector, and thus the arrangement ensures that the CMOS detector can detect the light field change in the optical waveguide sheet 10 in real time, thereby detecting whether the structure in the grating is normal, so that compensation and adjustment can be performed in time, and the imaging quality of the optical waveguide sheet 10 is ensured.

In the embodiment shown in fig. 1, there are two coupling-in gratings 20, the two coupling-in gratings 20 are respectively located at two opposite sides of the turning grating 30, a connection line between the center of the coupling-in grating 20 and the center of the turning grating 30 is perpendicular to a connection line between the center of the coupling-out grating 40 and the center of the turning grating 30, and the coupling-out grating 40 couples light out of the optical waveguide sheet 10. The coupling-out grating 40 is located at one side of the turning grating 30, and a connection line between the center of the coupling-in grating 20 and the center of the turning grating 30 is perpendicular to a connection line between the center of the coupling-out grating 40 and the center of the turning grating 30, so that most of the effective light in the turning grating 30 can enter the coupling-out grating 40 for coupling out the light by the coupling-out grating 40, thereby ensuring the coupling-out efficiency of the optical waveguide sheet 10 and further ensuring the imaging quality of the optical waveguide sheet 10. The two incoupling gratings 20 couple light emitted from two external image sources into the turning grating 30 to increase the outcoupling efficiency of the optical waveguide structure.

Example two

The difference from the first embodiment is that the position of the detector 50 is different.

In the specific embodiment shown in fig. 2, the detectors 50 are disposed on the optical waveguide sheet 10 and two detectors 50 are respectively located on two opposite sides of the optical waveguide sheet 10. The slit grating 60 is not arranged on the optical waveguide sheet 10, and the detector 50 is arranged on the optical waveguide sheet 10, so that the optical waveguide sheet 10 and the detector 50 are integrally formed, the detector 50 can conveniently detect the light coupled into the optical grating 20 and not emitted to the turning grating 30 in real time, the volume of the optical waveguide structure is reduced, and the miniaturization of the optical waveguide structure is ensured.

In addition, the detectors 50 are disposed on two opposite sides of the optical waveguide sheet 10, so that the two detectors 50 can respectively receive the light that is not coupled into the turning grating 30 in the two coupling gratings 20 to determine whether the images of the two external image sources are synchronized and shifted.

EXAMPLE III

The difference from the second embodiment is that the structure of the turning grating is different.

As shown in fig. 3 to 6, the coupling-in grating 20 and the turning grating 30 are located on the same side of the optical waveguide 10, and the coupling-out grating 40 and the turning grating 30 are located on two opposite sides of the optical waveguide 10. The optical waveguide structure in the present embodiment is suitable for scenes of external image sources and coupling-out directions, and the optical waveguide sheet 10 in the present embodiment can be used in a large scene.

In the embodiment shown in fig. 3, when the coupling-out grating 40 and the turning grating 30 are located on two opposite sides of the optical waveguide sheet 10, the turning grating 30 is a two-dimensional grating, and the coupling-out grating 40 is a one-dimensional grating. Thus, the areas of the turning grating 30 and the coupling-out grating 40 are larger, the coupling-out efficiency of the optical waveguide structure is higher, and the coupling-out efficiency of the optical waveguide structure is greatly increased. The turning grating 30 adopts a two-dimensional grating, and light on the surface of one side of the turning grating 30 can be coupled out to the coupling-out grating 40, so that the coupling-out efficiency of the optical waveguide structure is greatly increased.

In the embodiment shown in fig. 6, there are two directions of light coupling from one incoupling grating 20 to the turning grating 30, and the two-dimensional grating has high coupling efficiency.

It is to be understood that the above-described embodiments are only a few, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise, and it should be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical waveguide structure, comprising:

an optical waveguide sheet (10);

a plurality of incoupling gratings (20), wherein the incoupling gratings (20) are arranged on the optical waveguide sheet (10), and the incoupling gratings (20) couple light emitted by an external image source into the optical waveguide sheet (10);

a turning grating (30), wherein the turning grating (30) is used for receiving the light of the coupling-in grating (20), and a plurality of coupling-in gratings (20) are arranged around the turning grating (30) at intervals in the circumferential direction;

an out-coupling grating (40), the out-coupling grating (40) being adapted to receive light of the turning grating (30);

the detectors (50) are multiple, and the multiple detectors (50) are respectively located on one sides, far away from the turning grating (30), of the multiple incoupling gratings (20) and used for receiving light which does not enter the turning grating (30) in the incoupling gratings (20).

2. The optical waveguide structure according to claim 1, wherein the detector (50) is spaced apart from the optical waveguide sheet (10), the optical waveguide structure further comprises a plurality of slit gratings (60), the slit gratings (60) are disposed on the optical waveguide sheet (10), the slit gratings (60) are disposed in one-to-one correspondence with the detectors (50), and the slit gratings (60) are located in a light incident direction of the detectors (50).

3. Optical waveguide structure according to claim 2, characterized in that the detector (50) is located at the light entrance side of the optical waveguide sheet (10).

4. Optical waveguide structure according to claim 1, characterized in that the detectors (50) are arranged on the optical waveguide sheet (10) and that the two detectors (50) are located on opposite sides of the optical waveguide sheet (10), respectively.

5. The optical waveguide structure of claim 1,

the coupling-in grating (20), the turning grating (30) and the coupling-out grating (40) are all positioned on the same side surface of the optical waveguide sheet (10); or

The incoupling grating (20) and the turning grating (30) are positioned on the same side surface of the optical waveguide sheet (10), and the outcoupling grating (40) and the turning grating (30) are positioned on two opposite side surfaces of the optical waveguide sheet (10).

6. The optical waveguide structure of claim 5, wherein the coupling-out grating (40) is a two-dimensional grating and the turning grating (30) is a one-dimensional grating when the coupling-out grating (40) and the turning grating (30) are located on two opposite sides of the optical waveguide sheet (10).

7. Optical waveguide structure according to any one of claims 1 to 6, characterized in that the incoupling grating (20) is a diffraction grating.

8. The optical waveguide structure of claim 7, wherein the period of the diffraction grating is equal to or greater than 300 nanometers and equal to or less than 600 nanometers.

9. The optical waveguide structure according to any one of claims 1 to 6,

the optical waveguide sheet (10) is made of glass; and/or

The thickness of the optical waveguide sheet (10) is not less than 400 micrometers and not more than 1 millimeter;

the coupling-out grating (40) is one of a blazed grating, an inclined grating and a rectangular grating; and/or

The detector (50) is a CMOS detector (50).

10. The optical waveguide structure according to any one of claims 1 to 6, wherein there are two in-coupling gratings (20), two in-coupling gratings (20) are respectively located on two opposite sides of the turning grating (30), a connecting line between a center of the in-coupling grating (20) and a center of the turning grating (30) is perpendicular to a connecting line between a center of the out-coupling grating (40) and a center of the turning grating (30), and the out-coupling grating (40) couples the light out of the optical waveguide sheet (10).