CN213715501U

CN213715501U - Optical waveguide assembly and head-mounted display

Info

Publication number: CN213715501U
Application number: CN202022844147.2U
Authority: CN
Inventors: 朱耀明; 王方舟; 张韦韪
Original assignee: Shenzhen Huynew Technology Co ltd
Current assignee: Shenzhen Huynew Technology Co ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2021-07-16
Anticipated expiration: 2030-11-30

Abstract

The utility model provides an optical waveguide subassembly and wear-type display relates to the technical field of integrated grating, for solving prior art, grating waveguide product can't satisfy big angle of vision, hi-lite and the even technical problem of demonstration in the full field of vision under frivolous prerequisite, the technical scheme of the utility model as follows: a projection module; a waveguide element located in a projection light irradiation direction of the projection module; the coupling element is arranged on the waveguide element and comprises an incoupling grating, an expansion grating and an outcoupling grating which are all reflection-type, and the incoupling grating, the expansion grating and the outcoupling grating comprise side reflecting surfaces, top reflecting surfaces and groove reflecting surfaces; the groove reflecting surface of the incoupling grating is of an inclined structure, and the side reflecting surface and/or the top reflecting surface of the incoupling grating is of an inclined structure; the groove reflecting surface of the expanded grating is of an inclined structure; the groove reflecting surface of the coupling-out grating is of an inclined structure.

Description

Optical waveguide assembly and head-mounted display

Technical Field

The utility model relates to a technical field of integrated grating, in particular to optical waveguide subassembly.

Background

Augmented Reality (abbreviated as AR) glasses generate virtual information or images matched with real world sensing and calculation through the sensing and calculation of the real world, and are overlapped with the real world through an optical display system, so that the sensing of a user to the real world is increased. The AR glasses relate to key technologies such as environment recognition, tracking and positioning, three-dimensional registration and modeling, image rendering, projection display and the like. The AR optical system is a core technology of AR intelligent glasses projection display, and comprises a light source and display optics. The development of optical display schemes has evolved into a variety of technical routes, including prism, Bird Bath (Bird Bath), free-form surface and slab waveguide, wherein slab waveguide is widely regarded as the mainstream scheme of future AR optics due to its features of lightness, thinness, high transmittance, wide peripheral window and large exit pupil, and becomes one of the hot spots of research.

The slab waveguide is divided into two types, an array waveguide and a grating waveguide, according to the different modes of deflecting and transmitting light beams.

The arrayed waveguide utilizes the polarization characteristic of light, adopts a polarization film to reflect an outcoupled light beam, and simultaneously utilizes a plurality of cascaded polarization interfaces to realize one-dimensional expansion. The advantages are that the adopted broadband optical element has excellent color display performance, small problems of color cast and dispersion, mature cold processing technology and obvious advantages of industrial chain resources. But the defects are obvious, the requirement of a multi-chip cascade structure on the process manufacturing is high, the overall yield is limited, so that the existing common products are expanded products with only one dimension, the eye window is small, and the problem of ghost images needs to be solved.

The grating waveguide uses the diffraction characteristics of the grating to deflect, couple in and out the light beam. The grating waveguide has the advantages that the design is more flexible, the exit pupil expansion is more conveniently realized to obtain a large eye movement range, meanwhile, the equal-production process of nano imprinting and contact copying is more suitable for batch production, and the grating waveguide has outstanding advantages in the aspects of capacity and cost; the grating element is a narrow-band optical element, wavelength bandwidth and angle bandwidth bring great challenges to full-color display and large-angle-range display, and at present, industrial researchers all use the principle of multiplexing and superposition to realize the two functions, and the scheme can sacrifice the characteristics of light and thin engineering and the like to a certain extent.

In summary, the conventional grating waveguide product cannot satisfy the effects of large field angle, high brightness and uniform display in the full field of view on the premise of being light and thin in size.

SUMMERY OF THE UTILITY MODEL

For solving prior art, grating waveguide product can't satisfy big angle of vision, hi-lite and show even technical problem in the full field of vision under frivolous prerequisite, the technical scheme of the utility model as follows:

in one aspect, the utility model provides an optical waveguide component, include: a projection module; a waveguide element located in a projection light irradiation direction of the projection module; the coupling element is arranged on the waveguide element and comprises an incoupling grating, an expansion grating and an outcoupling grating which are all reflection-type, and the incoupling grating, the expansion grating and the outcoupling grating comprise side reflecting surfaces, top reflecting surfaces and groove reflecting surfaces; the groove reflecting surface of the incoupling grating is of an inclined structure, and the side reflecting surface and/or the top reflecting surface of the incoupling grating is of an inclined structure; the groove reflecting surface of the expanded grating is of an inclined structure; the groove reflecting surface of the coupling-out grating is of an inclined structure; projection light emitted by the projection module enters the waveguide element, is reflected by the coupling-in grating to deflect the angle of the light to be transmitted in the waveguide element in a total reflection manner, is diffracted and expanded by the expansion grating, and finally is emitted to the view field of an observer by the coupling-out grating.

Wherein the inclined structure is defined as: with inclination with respect to a horizontal or vertical plane, for example: the side reflecting surface is of an inclined structure, which means that the side reflecting surface has an inclined angle relative to a vertical surface; the top reflecting surface is of an inclined structure, which means that the top reflecting surface and a horizontal plane have an inclined angle; the groove reflecting surface is of an inclined structure, which means that the groove reflecting surface has an inclined angle with the horizontal plane.

The utility model provides an optical waveguide component, wherein, the incoupling grating, extension grating and coupled grating all are the reflection-type grating, their grating tooth has the side plane of reflection, the top plane of reflection, the slot plane of reflection has between the grating tooth, utilize the characteristic of the great bandwidth of reflection optics, through increasing grating structure reflection factor, the side plane of reflection promptly, top plane of reflection and slot plane of reflection all design the slope structure, with this enlarge the great angular range of grating response efficiency, allow the projection light of more wide-angle range can more effectual entering waveguide and coupled waveguide, promote the average diffraction efficiency in the response angle bandwidth, promote dull and stereotyped waveguide light energy utilization ratio, make the waveguide product of big angle of vision (FOV), user experience is better, satisfy the user demand under the various scenes.

In one possible design, the side reflecting surface and the top reflecting surface of the extended grating are inclined structures; the side reflecting surface and the top reflecting surface of the coupling-out grating are of inclined structures. The design mode increases the reflection elements of the expanded grating and the coupled-out grating, and improves the efficiency and the angular bandwidth of the grating.

In one possible design, the side reflecting surfaces, the top reflecting surface and the groove reflecting surfaces of the coupling-in grating, the extension grating and the coupling-out grating are all inclined structures. The design mode further increases the reflection elements of the coupling-in grating, the expansion grating and the coupling-out grating, and improves the efficiency and the angular bandwidth of all the gratings.

In one possible embodiment, the two side reflecting surfaces are arranged in parallel or at an acute angle.

In one possible design, further comprising: and the imaging collimation lens is arranged between the projection module and the waveguide element, and the projection light emitted by the projection module enters the waveguide element after being collimated by the imaging collimation lens. The imaging collimation lens is used for collimating the light emitted by the projection module.

In one possible design, the projection module includes an illumination light source and a projection optical element, and the projection optical element is located in a light irradiation direction of the illumination light source.

The projection optical element is an LCoS galvanometer, a DLP galvanometer or an MEMS galvanometer.

Specifically, the working principles of the above projection modules are as follows:

LCoS projection, a novel reflective projection technology, has a very high light utilization rate, high brightness, good color, and very high resolution, and is currently used in high-end projector types. Before introducing the LCoS, an LCD projector is introduced, which is based on the principle that a backlight portion of an LCD panel is removed, and then a high-power backlight source is used to irradiate the LCD panel through a condenser lens. The principle of LCoS projection is similar to that of an LCD projector, a CMOS integrated circuit chip coated with liquid crystal silicon is used as a substrate of a reflective LCD, aluminum is plated after the CMOS integrated circuit chip is ground by an advanced process and is used as a reflector to form a CMOS substrate, then the CMOS substrate is attached to a glass substrate containing a transparent electrode, and then liquid crystal is injected for packaging.

DLP projection, the term is digital light processing projector, its core is the display chip, the advantage is that the color is good, the picture smear is small, long service life, high performance-to-price ratio. The principle of the digital micro-mirror device is that a DMD chip is used as an imaging device, and a projection technology for projecting images is realized by adjusting reflected light. Imaging is achieved by reflecting light off thousands of tiny mirrors.

MEMS projection refers to an optical MEMS device fabricated using optical MEMS technology that integrates a micro-mirror with a MEMS driver. By adopting the micro-mirror reflection projection technology, the brightness and the contrast are obviously improved, and the volume and the weight are obviously reduced.

In one possible design, a refractive index modulation layer is attached to the outside of the waveguide element. The light enters the waveguide element through the refractive index modulation layer, is totally reflected and transmitted in the waveguide element by deflecting the angle of the light through the coupled-in grating, is diffracted and expanded through the expansion grating, and finally is emitted to the visual field of an observer through the coupled-out grating.

In one possible design, the refractive index modulation layer is made of titanium dioxide and/or silicon dioxide. The refractive index of the titanium dioxide or silicon dioxide film is larger than that of the coupling-in grating, so that the coupling efficiency of the coupling-in grating can be improved.

In one possible design, the waveguide element comprises glass or resin. The waveguide element is usually made of a material with a high refractive index and low loss, such as glass, resin, etc.

In another aspect, the present invention provides a head-mounted display, including the above-mentioned optical waveguide assembly. The head-mounted display product adopting the optical waveguide component has the advantages of small size, light weight, thin thickness and the like, and can meet the effects of large field angle, high brightness and uniform display in the whole field of view.

Drawings

Fig. 1 is a schematic view of an optical waveguide assembly according to an embodiment of the present invention;

fig. 2 is a partial schematic view of an embodiment of an incoupling grating according to the present invention;

fig. 3 is a partial schematic diagram of an incoupling grating, an expansion grating, and an outcoupling grating according to another embodiment of the present invention;

fig. 4 is a partial schematic diagram of an in-coupled grating, an extended grating, and an out-coupled grating according to another embodiment of the present invention;

FIG. 5 is a partial schematic view of a prior art in-coupled grating;

fig. 6 is a schematic diagram of a diffraction curve provided by an embodiment of the present invention.

Reference numerals: 10. a projection module; 11. an illumination light source; 12. a projection optical element; 20. a waveguide element; 30. a coupling element; 31. coupling in a grating; 311. a side reflective surface; 312. a top reflective surface; 313. a groove reflective surface; 32. expanding the grating; 33. coupling out the grating; 40. an imaging collimating lens.

Detailed Description

The technical solution of the present invention will be described below with reference to the accompanying drawings. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "side", "inner", "outer", "top", "bottom", and the like, indicate orientations or positional relationships based on installation, and are merely for convenience of description and simplicity of description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature.

It should be noted that, in the embodiments of the present invention, the same reference numerals are used to denote the same components or parts, and for the same components or parts in the embodiments of the present invention, only one of the components or parts may be used as an example to denote the reference numeral in the drawings, and it should be understood that the reference numerals are also applicable to other similar components or parts.

As shown in fig. 1 to 4, the present embodiment provides an optical waveguide assembly including: a projection module 10; a waveguide element 20 located in a projection light irradiation direction of the projection module 10; a coupling element 30 disposed on the waveguide element 20, wherein the coupling element 30 includes a coupling-in grating 31, an expansion grating 32 and a coupling-out grating 33, which are reflective types, and the coupling-in grating 31, the expansion grating 32 and the coupling-out grating 33 include a side reflective surface 311, a top reflective surface 312 and a groove reflective surface 313; the groove reflecting surface 313 of the incoupling grating 31 is in an inclined structure, and the side reflecting surface 311 and/or the top reflecting surface 312 of the incoupling grating 31 is in an inclined structure; the groove reflecting surface 313 of the extended grating 32 is an inclined structure; the groove reflecting surface 313 of the coupling-out grating 33 is of an inclined structure; projection light emitted by the projection module 10 enters the waveguide element 20, is totally reflected and transmitted in the waveguide element 20 by deflecting the light angle by the incoupling grating 31, is diffracted and expanded by the expansion grating 32, and finally is emitted to the view field of an observer by the outcoupling grating 33.

Wherein the definition of the inclined structure is as follows: with inclination with respect to a horizontal or vertical plane, for example: the side reflective surface 311 has an inclined structure, which means that the side reflective surface 311 has an inclination angle with respect to a vertical plane; the top reflective surface 312 is an inclined structure, which means that the top reflective surface 312 has an inclined angle with the horizontal plane; the groove reflection surface 313 has an inclined structure, which means that the groove reflection surface 313 has an inclination angle with respect to a horizontal plane.

In the present invention, the groove reflection surface 313 of the coupling grating 31 must be an inclined structure, and the side reflection surface 311 and the top reflection surface 312 are inclined structures. The groove reflecting surfaces 313 of the extension grating 32 and the coupling-out grating 33 must also be inclined, and both of the inclined structures of the side reflecting surface 311 and the top reflecting surface 312 may be selected or not selected.

As shown in fig. 5, the side reflective surface 311, the top reflective surface 312 and the groove reflective surface 313 of the conventional grating in the prior art are designed, and it can be seen that there is no inclination angle with the horizontal plane or the vertical plane. As shown in fig. 6, it is the utility model discloses in adopt the coupled grating 31 of inclined reflecting surface and the conventional grating among the prior art, at the diffraction curve that-11-11 within ranges correspond, wherein, the dotted line does the utility model discloses in adopt the coupled grating 31's of inclined reflecting surface diffraction curve, the solid line is the diffraction curve of conventional grating among the prior art, can see out, its diffraction intensity of grating obviously is greater than the diffraction intensity of conventional grating.

As shown in fig. 2, in one embodiment, the top reflective surface 312 and the trench reflective surface 313 of the incoupling grating 31 are slanted structures. The top reflecting surface 312 and the groove reflecting surface 313 are designed in an inclined manner, reflection factors are enhanced, the efficiency and the angular bandwidth of the grating are improved, and the diffraction efficiency corresponding to the angular range of-11 to 11 degrees shows that the top reflecting surface 312 and the groove reflecting surface 313 with the inclined reflecting surfaces enable the grating to have relatively large diffraction efficiency in a larger angular range, so that all the angle light rays projected by the projection module 10 with a large field angle can be coupled into the waveguide element 20 by the coupling-in grating 31, and the diffraction efficiency corresponding to all the angle light rays is at a considerable level, so that the uniformity of a projected image is guaranteed.

As shown in fig. 3-4, in one embodiment, the side reflective surfaces 311, the top reflective surface 312, and the groove reflective surface 313 of the incoupling grating 31, the expansion grating 32, and the outcoupling grating 33 are all inclined structures, and the two side reflective surfaces 311 are arranged in parallel or at an acute angle. The structure design of the coupling-in grating 31, the extension grating 32 and the coupling-out grating 33 to expand the bandwidth can also adopt other design schemes, as shown in fig. 3, the side reflecting surface 311 is inclined, and the two side reflecting surfaces 311 are parallel, so that the efficiency of the grating is increased to a certain extent, and the efficiency of the grating in the angular bandwidth is more average. As shown in fig. 4, the two side reflective surfaces 311 are both inclined and are not parallel, so that the shielding of the inclined side reflective surface 311 to the partial angle light can be reduced, and the efficiency of each angle light in the angle range can be improved.

In the optical waveguide component provided in this embodiment, the incoupling grating 31, the expansion grating 32, and the outcoupling grating 33 are all reflective gratings, grating teeth of the gratings have side reflective surfaces 311 and top reflective surfaces 312, and trench reflective surfaces 313 are provided between the grating teeth, so that by increasing reflective elements of the grating structure, that is, the side reflective surfaces 311, the top reflective surfaces 312, and the trench reflective surfaces 313 are all designed as inclined structures, an angular range with a large grating response efficiency is expanded, projection light in a larger angular range is allowed to enter the waveguide and be coupled out of the waveguide more effectively, an average diffraction efficiency within a response angular bandwidth is improved, a utilization rate of planar waveguide light energy is improved, a waveguide product with a large field of view (FOV) is made, user experience is better, and user requirements under various scenes are met.

In one embodiment, further comprising: and the imaging collimating lens 40 is arranged between the projection module 10 and the waveguide element 20, and the projection light emitted by the projection module 10 enters the waveguide element 20 after being collimated by the imaging collimating lens 40. The image collimating lens 40 is used for collimating the light emitted from the projection module 10.

In one embodiment, the projection module 10 includes an illumination light source 11 and a projection optical element 12, and the projection optical element 12 is located in a light irradiation direction of the illumination light source 11. The projection optical element 12 is an LCoS galvanometer, a DLP galvanometer, or an MEMS galvanometer, preferably an MEMS galvanometer.

In one embodiment, a refractive index modulation layer is attached to the outside of the waveguide element 20. The light enters the waveguide element 20 through the refractive index modulation layer, is totally reflected and transmitted in the waveguide element 20 by deflecting the angle of the light through the incoupling grating 31, is diffracted and expanded through the expansion grating 32, and finally exits to the view field of an observer through the outcoupling grating 33.

In one embodiment, the refractive index modulation layer is made of titanium dioxide and/or silicon dioxide. The refractive index of the titanium dioxide or silicon dioxide film is greater than that of the coupling-in grating 31, so that the coupling efficiency of the coupling-in grating 31 can be improved.

In one embodiment, the waveguide element 20 comprises glass or resin. The waveguide element 20 is usually made of a material with a high refractive index and low loss, such as glass, resin, or the like.

The embodiment provides a head-mounted display which comprises the optical waveguide component. The head-mounted display product adopting the optical waveguide component has the advantages of small size, light weight, thin thickness and the like, and can meet the effects of large field angle, high brightness and uniform display in the whole field of view.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An optical waveguide assembly, comprising:

a projection module (10);

a waveguide element (20) located in a projection light irradiation direction of the projection module (10);

a coupling element (30) disposed on the waveguide element (20), wherein the coupling element (30) includes an incoupling grating (31), an expansion grating (32), and an outcoupling grating (33) which are reflective, and the incoupling grating (31), the expansion grating (32), and the outcoupling grating (33) include side reflective surfaces (311), a top reflective surface (312), and a groove reflective surface (313); the groove reflecting surface (313) of the coupling-in grating (31) is of an inclined structure, and the side reflecting surface (311) and/or the top reflecting surface (312) of the coupling-in grating (31) are of an inclined structure; the groove reflecting surface (313) of the extended grating (32) is of an inclined structure; the groove reflecting surface (313) of the coupling-out grating (33) is of an inclined structure;

projection light emitted by the projection module (10) enters the waveguide element (20), is totally reflected and transmitted in the waveguide element (20) by the angle of the deflected light of the incoupling grating (31), is diffracted and expanded by the expansion grating (32), and finally is emitted to the view field of an observer by the outcoupling grating (33).

2. The optical waveguide assembly of claim 1, wherein the side reflective surface (311) and the top reflective surface (312) of the expansion grating (32) are slanted structures; the side reflecting surface (311) and the top reflecting surface (312) of the coupling-out grating (33) are of an inclined structure.

3. Optical waveguide component according to claim 1, characterized in that the coupling-in grating (31), the expansion grating (32), the side reflecting surface (311), the top reflecting surface (312) and the trench reflecting surface (313) of the coupling-out grating (33) are all slanted structures.

4. Optical waveguide component according to claim 1, characterized in that the two side reflecting surfaces (311) are arranged in parallel or at an acute angle.

5. The optical waveguide assembly of claim 1, further comprising:

the imaging collimation lens (40) is arranged between the projection module (10) and the waveguide element (20), and projection light emitted by the projection module (10) enters the waveguide element (20) after being collimated by the imaging collimation lens (40).

6. The optical waveguide assembly of claim 1, wherein the projection module (10) comprises an illumination light source (11) and projection optics (12), the projection optics (12) being located in a light irradiation direction of the illumination light source (11).

7. Optical waveguide component according to claim 1, characterized in that a refractive index modulation layer is applied to the outside of the waveguide element (20).

8. The optical waveguide assembly of claim 7 wherein the refractive index modulating layer is formed of titanium dioxide and/or silicon dioxide.

9. Optical waveguide component according to claim 1, characterized in that the waveguide element (20) comprises glass or resin.

10. A head-mounted display comprising the optical waveguide assembly of any one of claims 1-9.