CN113126292A

CN113126292A - Near-to-eye display system

Info

Publication number: CN113126292A
Application number: CN201911412936.4A
Authority: CN
Inventors: 不公告发明人
Original assignee: Chengdu Idealsee Technology Co Ltd
Current assignee: Chengdu Idealsee Technology Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-07-16

Abstract

The embodiment of the application discloses near-eye display system, near-eye display system includes at least: optical display module assembly and waveguide, wherein: the optical display module outputs image light beams, the waveguide is arranged on a transmission light path of the image light beams, a complete view field corresponding to the image light beams output by the optical display module is coupled into the coupling-in unit of the waveguide in an asymmetric mode, and the image light beams are expanded in the horizontal direction and/or the vertical direction through the waveguide and then are output to human eyes through the coupling-out unit of the waveguide. The near-to-eye display system can avoid field loss to a certain extent under the condition that the waveguide grating constant is small enough.

Description

Near-to-eye display system

Technical Field

The application relates to the technical field of scanning display, in particular to a near-to-eye display system.

Background

Waveguide (waveguide) is widely used in Augmented Reality (AR) devices as an important optical device. As shown in fig. 1a, a simplified block diagram of a typical AR device from a top view is shown. The left and right pieces of waveguides correspond to the left and right eyes of the user, respectively. Referring to fig. 1b, an optical structure diagram of an AR device side is shown, in which a parallel light beam output from the optical module 01 is projected onto an incoupling unit 024 of the waveguide 02, the incoupling unit 024 guides the light beam into the waveguide 02 to propagate to an outcoupling unit 026 by total reflection, and the outcoupling unit 026 guides the light beam out of the waveguide 02 to a human eye.

When the user actually wears the AR device, external ambient light may also enter the human eye through the waveguide 02. Specifically, as shown in fig. 1c, the external environment light generates diffracted beams of multiple diffraction orders under the diffraction action of the coupling-out unit 026, and fig. 1c only illustrates the diffraction order of a beam of a certain wavelength band, and actually, the external environment light has a wide spectrum, and beams of different wavelength bands generate diffracted beams of multiple diffraction orders, so that a rainbow effect seen by human eyes is formed, and the effect of a virtual image displayed by the AR device is affected.

Some current solutions to the rainbow effect (e.g. chinese patent CN109073894A) generally reduce the grating constant of the out-coupled grating. After the grating constant is reduced, the interval between the beams of different diffraction orders is larger, so that the number of the high-order diffracted beams entering human eyes can be reduced, and the aim of inhibiting the rainbow effect is fulfilled.

However, the above scheme introduces a new technical problem: in general, the grating constants of the coupling-in grating and the coupling-out grating are matched the same, and when the grating constant of the coupling-out grating is reduced, the grating constant of the coupling-in grating should be correspondingly reduced, which may cause the field of view of the image output by the optical module to be reduced due to the influence of the grating constant of the coupling-in grating, and further cause the effective field of view range corresponding to the light beam output from the waveguide to be reduced.

Disclosure of Invention

The application aims to provide a near-eye display system which is used for reducing or avoiding the problem that the field of view is influenced because a waveguide adopts a small grating constant.

An embodiment of the present application provides a near-to-eye display system, which at least includes: an optical display module and a waveguide, wherein,

the optical display module outputs an image light beam;

the waveguide is arranged on a transmission light path of the image light beam, and a complete view field corresponding to the image light beam output by the optical display module is coupled into the coupling-in unit of the waveguide in an asymmetric mode, and is output to human eyes by the coupling-out unit of the waveguide after being expanded in the horizontal direction and/or the vertical direction through the waveguide.

Optionally, the first side subfield is: in a complete view field corresponding to the image light beam output by the optical display module, the incident angle of the image light beam in the first side sub view field relative to the coupling-in unit is smaller than the incident angle of the image light beam in the second side sub view field relative to the coupling-in unit; wherein the content of the first and second substances,

the first side subfield is: the visual field which is output by the optical display module and is inclined towards one side of the position where the coupling-out unit is located in the horizontal direction corresponds to the image light beam;

the second side subfield is: and the visual field which is output by the optical display module and corresponds to the image light beam on the other side of the position where the coupling-out unit is located in the horizontal direction.

Optionally, the incident angle corresponding to the image beam in the first side subfield is smaller than the incident angle corresponding to the image beam in the second side subfield.

Optionally, the optical display module at least comprises: an image display module and an optical lens group;

the image display module is used for outputting an image light beam;

the optical lens group is arranged on a light path of the image light beam and comprises one or more lenses for carrying out optical processing on the image light beam;

wherein the optical processing comprises at least: one of collimating, shaping, and correcting the image beam.

Optionally, the image display module is a panel display module;

wherein, panel display module assembly includes at least: a silicon-based liquid crystal LCOS, an organic light emitting diode OLED, a Micro-LED.

Optionally, a surface of the panel-type display module is parallel to lenses of the optical lens group, and the panel-type display module and the lenses of the optical lens group are arranged obliquely with respect to a surface of the coupling-in unit of the waveguide.

Optionally, a panel surface of the panel display module is parallel to an incoupling unit surface of the waveguide, and the lenses of the optical lens group are disposed obliquely with respect to the panel surface of the panel display module and the incoupling unit surface.

Optionally, the optical lens group is obliquely arranged as follows: in the horizontal direction, the distance from the side of the lens in the optical lens group close to the waveguide light-out region to the surface of the coupling-in unit is smaller than the distance from the side of the lens far away from the waveguide light-out region to the surface of the coupling-in unit.

Optionally, the image display module is a scanning display module;

wherein, scanning formula display module assembly includes: including a microelectromechanical system MEMS scanning mirror or a fiber optic scanner.

Optionally, the scanning display module is a MEMS scanning mirror.

Optionally, the mirror plate of the MEMS scanning mirror is parallel to the mirror plate of the optical lens group in a resting state, and the mirror plate of the MEMS scanning mirror and the mirror plate of the optical lens group are disposed together in an inclined manner with respect to the surface of the coupling-in unit of the waveguide;

when the MEMS scanning mirror is swept, the image light beams output by scanning cover the surface of the lens of the optical lens group.

Optionally, the mirror plate of the MEMS scanning mirror is parallel to the incoupling unit surface of the waveguide, and the mirror plate in the optical mirror group is disposed obliquely with respect to the mirror plate of the MEMS scanning mirror and the incoupling unit surface;

Optionally, the mirror plate of the MEMS scanning mirror is parallel to the mirror plate of the optical mirror group in a resting state, and the mirror plate of the optical mirror group is parallel to the coupling-in unit surface of the waveguide;

when the MEMS scanning mirror is scanned, the image light beam output by scanning covers a partial area on the surface of the lens of the optical lens group, which is close to one side of the light outlet area of the waveguide.

Optionally, the scanning display module is an optical fiber scanner.

Optionally, the scanning fiber of the fiber scanner is perpendicular to the mirror of the optical lens group in a static state, and the mirror is obliquely arranged relative to the surface of the coupling-in unit of the waveguide;

when the optical fiber scanner is swept, the image light beams output by scanning cover the lens surface of the optical lens group.

Optionally, the scanning optical fiber of the optical fiber scanner is perpendicular to the surface of the coupling-in unit of the waveguide in a static state, and the lens in the optical lens group is obliquely arranged relative to the scanning optical fiber and the surface of the coupling-in unit in the static state;

Optionally, the scanning optical fiber of the optical fiber scanner is perpendicular to the mirror of the optical lens group in a static state, and the mirror of the optical lens group is parallel to the surface of the coupling-in unit of the waveguide;

when the optical fiber scanner scans, the scanned and output image light beam covers a partial area on the surface of the lens of the optical lens group, which is deviated to one side of the light outlet area of the waveguide.

Optionally, the light exit end surface of the scanning optical fiber is an inclined surface.

Optionally, the number of the optical display modules is two, and the optical display modules are respectively used for outputting image light beams corresponding to two eyes.

Optionally, the waveguide is at least two stacked waveguides, the image light beams of the asymmetric viewing fields output by the two optical display modules are respectively input into the two stacked waveguides, and the image light beams output by each stacked waveguide are input to human eyes after being subjected to viewing field splicing.

Optionally, the waveguide is an integrated waveguide, and includes a left coupling-in unit and a right coupling-out unit, and a common coupling-out unit, where the image light beams of the asymmetric viewing fields output by the two optical display modules are input to the waveguide from the left coupling-in unit and the right coupling-in unit, respectively, and the image light beams are output to human eyes after being subjected to viewing field splicing on the common coupling-out unit.

By adopting the technical scheme in the embodiment of the application, the following technical effects can be realized:

in the conventional near-eye display system, the field of view input from the optical display module to the waveguide coupling-in unit is generally symmetrical, but as the grating constant of the waveguide is reduced, diffracted light beams generated by light beams of the left sub-field of view are easy to exceed 90 degrees, and further the transmission condition of the light beams in the waveguide is damaged.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

FIG. 1a is a schematic diagram of a near-eye display system for use in a near-eye display device;

FIG. 1b is a schematic diagram of the optical path in the near-eye display system shown in FIG. 1 a;

FIG. 1c is a schematic diagram of a diffracted beam of external ambient light generated through a waveguide;

FIG. 2a is an illustrative schematic of a waveguide three-dimensional structure;

FIGS. 2b and 2c are illustrative schematic diagrams of an incident beam entering a waveguide and its diffracted beams;

FIG. 2d is a schematic diagram of the light beam output by the optical display module being incident on the waveguide entrance pupil;

FIGS. 3a and 3b are schematic diagrams of the light paths of the light beams incident on the waveguide for the symmetrical left and right fields of view;

FIGS. 4a and 4b are schematic diagrams of light paths of light beams incident on the waveguide in asymmetric left and right fields of view in the embodiment of the present application;

FIG. 5 is a schematic structural diagram of an optical display module according to an embodiment of the present disclosure;

FIGS. 6a and 6b are schematic views illustrating an arrangement of panel-type display modules generating an asymmetric viewing field according to an embodiment of the present disclosure;

FIGS. 7 a-7 c are schematic diagrams of an arrangement for generating an asymmetric field of view using a MEMS scanning mirror in an embodiment of the present application;

FIGS. 8 a-8 d are schematic diagrams illustrating an arrangement of an asymmetric field of view generated by a fiber scanner according to an embodiment of the present application;

FIGS. 9a and 9b are schematic diagrams of the output of the light beams incident on the left and right waveguides in the asymmetric field of view in the embodiment of the present application

Fig. 10a and 10b are schematic diagrams of optical paths and related parameters when field stitching is performed in the embodiment of the present application.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the related invention are shown in the drawings.

Analyzing optical path of waveguide transmission

As shown in fig. 2a, taking a side waveguide 200 as an example, a three-dimensional structure of the waveguide 200 is shown in fig. 2a, and a light beam entering the waveguide 200 through a coupling-in unit 201 can be expanded in the horizontal direction and the vertical direction, and is output from the waveguide 200 by the action of a coupling-out unit 202 to enter the human eye.

It should be noted that, in this and the following embodiments, the two directions, namely, the horizontal direction and the vertical direction, which are referred to when describing the waveguide, can be regarded as relative to the waveguide itself, that is, as shown in fig. 2a, the direction of the light beam entering the waveguide 200 from the coupling-in unit 201 for transverse transmission can be referred to as the horizontal direction, the propagation direction perpendicular to the horizontal direction can be referred to as the vertical direction, and the definitions of the horizontal direction and the vertical direction are independent of the wearing posture of the user after wearing the waveguide, that is, the definitions of the horizontal direction and the vertical direction in the present embodiment are not affected no matter how the user twists and tilts the head.

It should be understood that the waveguide structure shown in fig. 2a is an exemplary structure only for facilitating understanding of the scheme of the present application, and in fact, the structure of the waveguide is not limited thereto, for example: relay members may also be provided in the waveguide, or the incoupling unit of the waveguide may be provided elsewhere (e.g. on the top side of the waveguide in fig. 2 a).

Referring to fig. 2b, which shows a portion of the waveguide 200 from a top view, a certain incident beam 22 is incident on the coupling-in unit 201 of the waveguide 200, where an incident angle (i.e. an angle between the incident beam 22 and a normal) corresponding to the incident beam 22 is denoted as a₁The coupling-in unit 201 may be a grating, the incident light beam 22 is diffracted after passing through the coupling-in unit 201 to generate a diffracted light beam, for convenience of description and understanding, only two diffracted light beams 240 of the same order are taken as an example for illustration, and the diffraction angles of the two diffracted light beams 240 of the same order are the same (i.e. the included angles with the normal are the same), which are denoted as b₁Angle of incidence a of incident beam 22₁And the diffraction angle b of the diffracted beam 240₁Satisfies the following formula:

d[sin(a₁)+nsin(b₁)]＝mλ (1)

where d is the grating constant, m is the diffraction order, λ is the wavelength of the incident beam 22, and n is the waveguide refractive index.

As shown in fig. 2c, another incident light beam 23 is incident on the coupling-in unit 201 of the waveguide 200 from another direction of symmetry, where the incident angle of the incident light beam 23 is denoted as a₂The incident beam 23 is diffracted after passing through the coupling-in unit 201, and a corresponding diffracted beam is generated,here, similarly, only two diffracted beams 250 of the same order are taken as an example for explanation, and the diffraction angles of the two diffracted beams 250 of the same order are also the same, and are denoted as b herein₂Similarly, the incident angle a of incident beam 23₂And the diffraction angle b of the diffracted beam 250₂Satisfies the following formula:

d[sin(a₂)+nsin(b₂)]＝mλ (2)

the parameters can refer to the definitions of the parameters in the formula (1), and are not described herein again.

With reference to fig. 2b and 2c, the following calibration can be made:

if an incident beam is incident on the incoupling unit 201 from the left side of the normal, the incident angle of the incident beam is denoted as a₁<0, further, if the diffracted beam and the incident beam are both on the same side of the normal, the diffraction angle of the diffracted beam is denoted as b₁<0, correspondingly, if the diffracted beam and the incident beam are located on the opposite side of the normal, the diffraction angle of the diffracted beam is denoted as b₁>0。

If an incident beam is incident on the incoupling unit 201 from the right side of the normal, the incident angle of the incident beam is denoted as a₂>0, further, if the diffracted beam and the incident beam are both on the same side of the normal, the diffraction angle of the diffracted beam is denoted as b₂>0, correspondingly, if the diffracted beam and the incident beam are located on the opposite side of the normal, the diffraction angle of the diffracted beam is denoted as b₂<0。

Of course, for the waveguide on the other side (which is understood to correspond to the waveguide of the other eye, not shown in fig. 2a or 2 b), it is mirror symmetric with the waveguide 200, so the calibration relationship on the waveguide on the other side is opposite to the above calibration relationship, and the description thereof is omitted here.

It should be noted that, as shown in fig. 2d, in an illustrative optical system, the incident light beam is output by an optical module, which may include, for example, a lens, an image display module, and the like, which will be described in detail later, and will not be described in detail herein. During actual display, under the action of the lens, the light beams are output to the coupling-in unit 201 from the light-emitting end face F of the optical module and form a complete field of view, the complete field of view includes a plurality of sub-fields of view at different angles, and the light beams in each sub-field of view are parallel light beams. Only 2 different angles of sub-fields are shown in fig. 2d, which in order from left to right are: a left sub-field and a right sub-field. The light beams in the respective subfields will be transmitted to the same region on the surface of the incoupling unit 201 of the waveguide 200, and this region is referred to as an entrance pupil (may be simply referred to as "entrance pupil") of the waveguide 200. The left and right subfields in fig. 2d are symmetric subfields with respect to each other, and the incident angles of the light beams in the two subfields to the surface of the coupling-in unit 201 are the same.

In the following, for ease of understanding and description, the multiple light beams in the subfield can be simplified into one light beam, and the entrance pupil of the waveguide 200 is simplified into a central point on the incoupling unit 201.

Based on the above, with further reference to fig. 3a and 3b, in the top view of fig. 3a and 3b, a black line is used to represent the light-emitting end face F of the optical display module.

Specifically, referring to fig. 3a, the leftmost sub-field of view output from the light-exiting end face F is represented as a beam (the beam may be referred to as an incident beam 31 with respect to the coupling-in unit 201). The incident beam 31 is incident on the entrance pupil of the incoupling unit 201, and based on the above calibration, the angle a between the incident beam 31 and the normal perpendicular to the surface of the incoupling unit 201 is known₁<0, incident beam 31 passes through the coupling-in unit 201 to generate diffracted beam 32 (only one diffracted beam is shown in fig. 3a for convenience of illustration and understanding), and diffracted beam 32 and incident beam 31 are located on different sides of the normal, so that angle b between diffracted beam 32 and the normal is determined according to the above-mentioned calibration relationship₁>0。

In this case, the incident angle b of the diffracted beam 32 can be found based on the above formula (1)₁Satisfies the following conditions:

similarly, referring to fig. 3b, the rightmost subfield is also represented as a beam (which may be referred to as a beam with respect to the coupling-in unit 201Incident light beam 33). The incident beam 33 is incident on the entrance pupil of the incoupling unit 201, and based on the above calibration, the angle a between the incident beam 33 and the normal perpendicular to the surface of the incoupling unit 201 is known₂>0, the incident beam 33 passes through the coupling-in unit 201 to generate a diffracted beam 34 (also, only one diffracted beam is shown in fig. 3 b), the diffracted beam 34 is located on the same side of the normal as the incident beam 33, so that the angle b between the diffracted beam 34 and the normal is determined according to the above-mentioned calibration relationship₂>0。

In this case, the diffraction angle b of the diffracted beam 34 can be found based on the above formula (2)₂Satisfies the following conditions:

by combining the above expressions of two diffraction angles, it can be seen that the incident angle of the incident beam is the same (i.e. | a)₁|＝|a₂|)), the diffraction angles of the diffracted

beams

33, 34 satisfy: | b₁|>|b₂L. Meanwhile, to ensure that the diffracted

beams

33, 34 can be transmitted by total reflection in the waveguide, the diffraction angles of the diffracted

beams

33, 34 further satisfy: 90 degree>|b₁|>|b₂|>θ_CWherein, in the step (A),

θ_Cis the angle of total reflection.

As mentioned above, some solutions reduce the grating constant d to solve the rainbow effect, but after reducing the grating constant d, | b according to the formula₁|、|b₂All become larger, especially for | b₁In the case of | b, it may result in |₁The angle is more than or equal to 90 degrees, so that the transmission condition in the waveguide is not met any more, obviously, the light beam which does not meet the transmission condition in the waveguide can not be totally reflected in the waveguide and finally enters the human eye, and the condition that partial view field images are lost is caused.

To this end, the embodiment of the present application provides a corresponding near-eye display system.

In the following embodiments, for convenience of description and understanding, only one side (corresponding to a single eye) waveguide is generally taken as an example for description, and uniform reference numerals are used for the waveguide and the coupling-in unit and the coupling-out unit thereof, which should not be construed as limiting the present application.

Near-to-eye display system with asymmetric field of view

Referring to fig. 4a and 4b, schematic optical path diagrams of a near-eye display system with an asymmetric field of view corresponding to a single eye in an embodiment of the present application are shown. In fig. 4a and 4b, the light beams used to characterize the leftmost sub-field and the rightmost sub-field of the optical display module (not shown in fig. 4a and 4 b) are shown, respectively. The two light beams can enter the waveguide 200 through the coupling-in unit 201 for transmission and are output from the waveguide 200 to the human eye through the coupling-out unit 202. The incident angles of the two light beams on the waveguide 200 coupling unit 201 are asymmetric, that is, the leftmost sub-field and the rightmost sub-field output by the optical display module are not symmetric.

Specifically, the incident angle (a) at which the light beam of the leftmost sub-field of view is incident to the coupling-in unit 201₁) An incident angle (a) at which the light beam smaller than the rightmost subfield is incident to the coupling-in unit 201₂) I.e., | A₁|<|A₂L. Obviously, with incident angle | A₁I is reduced, the diffraction angle | B of the diffraction beam generated after the image beam of the first side sub-field is incident on the coupling-in unit 201₁The | is also reduced, so that the | B can be avoided₁A situation where | reaches 90 ° resulting in a loss of field of view.

It should be understood that the leftmost sub-viewing field and the rightmost sub-viewing field output by the optical display module can be regarded as "boundaries" of the complete viewing field output by the optical display module, and on the basis that the leftmost sub-viewing field and the rightmost sub-viewing field are asymmetric, the left sub-viewing field and the right sub-viewing field of other angles output by the optical display module are also asymmetric. It should be noted that the left and right directions described herein are based on the top view as shown in fig. 4a and 4 b. Generally, the left and right subfields may be called: a first side subfield and a second side subfield. The first side sub-field of view can be considered as a sub-field of view output by the optical display module and tilted towards the direction of the coupling-out unit 202, and the second side sub-field of view can be considered as a sub-field of view output by the optical display module and tilted away from the direction of the coupling-out unit 202. In the top view shown in fig. 4a and 4b, the beams in the first side sub-field are deflected to the right, and the beams in the second side sub-field are deflected to the left.

In order to realize the asymmetric left and right visual fields output by the optical display module in the near-to-eye display system, the optical display module can adopt different setting modes.

Fig. 5 is a schematic diagram of a basic structure of an optical display module. Specifically, the optical display module 500 may further include: image display module 501 and optical lens group 502, image display module 501 is used for outputting image light beam, and optical lens group 502 sets up in image light beam's light path for carry out optical processing to image light beam, include but not limited to: collimated, shaped, corrected, etc., and the image beam processed by the optical lens group 502 is incident on a waveguide (not shown in fig. 5).

The image display module 501 shown in fig. 5 is only an illustration, and in fact, the image display module 501 may be divided into a panel display module and a scan display module according to different display modes. Wherein, panel-type display module includes but not limited to: liquid Crystal On Silicon (LCOS) panels, Organic Light-Emitting Diode (OLED) panels, Micro Light-Emitting Diode (Micro-LED) panels, and the like; the scanning display module includes but is not limited to: Micro-Electro-Mechanical systems (MEMS) scanning mirrors, fiber scanners, and the like.

The optical lens group 502 may be composed of a plurality of lens stacks with different functions, the optical lens group 502 shown in fig. 5 is only a simple illustration, and in the following, the optical lens group in the drawings is also presented in a similar simplified manner, and should not be construed as a limitation to the present application.

Panel type display module set setting mode

First setting mode

Referring to fig. 6a, the optical display module 60 includes: a display panel 601 and a corresponding optical lens group 602. In the optical display module 60, the panel surface of the display panel 601 is perpendicular to the optical axis of the optical lens assembly 602, in other words, the display panel 601 is parallel to the lens of the optical lens assembly 602, and preferably, the center of the panel surface of the display panel 601 is coaxial with the optical axis of the optical lens assembly 602. The optical display module 60 is disposed to be inclined with respect to the surface of the waveguide 200 coupling-in unit 201 as a whole.

In the view shown in fig. 6a, the specific inclination is: the side of the display panel 601 and the optical lens assembly 602 close to the light exit area of the waveguide 200 is closer to the surface of the coupling-in unit 201, and the side of the display panel 601 and the optical lens assembly 602 away from the light exit area of the waveguide 200 is farther from the surface of the coupling-in unit 201. Thereby forming the tilted state shown in fig. 6 a.

In such an inclined state, the image beam S of the first side subfield output from the optical mirror group 602₁The incident angle on the surface of the incoupling unit 201 will be smaller than the image beam S of the second side subfield output from the optical mirror group 602₂The angle of incidence on the surface of the incoupling unit 201.

Second arrangement

Referring to fig. 6b, in the optical display module 60, the panel surface of the display panel 601 is parallel to the coupling-in unit 201 of the waveguide 200, and the optical lens assembly 602 is disposed obliquely with respect to the display panel 601 and the coupling-in unit 201 of the waveguide 200, i.e. the optical axis of the optical lens assembly 602 is neither perpendicular to the surface of the coupling-in unit 201 nor perpendicular to the panel surface of the display panel 601.

The optical lens assembly 602 is inclined in the same manner as the first arrangement, i.e. the side of the optical lens assembly 602 close to the light exit area of the waveguide 200 is closer to the surface of the coupling-in unit 201, and the side of the optical lens assembly 602 away from the light exit area of the waveguide 200 is farther from the surface of the coupling-in unit 201. Thereby forming the tilted state shown in fig. 6 b.

In such an inclined state, the image beam S of the first side subfield output from the optical mirror group 602₁The incident angle on the surface of the incoupling unit 201 is smaller than the second side output from the optical mirror 602Image beam S of subfield₂The angle of incidence on the surface of the incoupling unit 201.

Both arrangements can make the incident angle of the image beam in the first side sub-field on the surface of the coupling-in unit 201 smaller than the incident angle of the image beam in the second side sub-field on the surface of the coupling-in unit 201. So that the effects expected in the present application can be achieved: as the incident angle corresponding to the image beam in the first side subfield is reduced, the diffraction angle of the diffracted beam generated after being incident on the incoupling unit 201 is also reduced, so that the situation that the field is lost due to the fact that the diffraction angle reaches 90 ° can be avoided.

It should be noted that, in the two embodiments corresponding to fig. 6a and fig. 6b, only the arrangement manner of the optical display module corresponding to a single eye (left eye or right eye) is shown, and the arrangement manner of the optical display module corresponding to another single eye (right eye or left eye) is symmetrically opposite to the arrangement manner shown in the two embodiments, and redundant description is omitted here.

Setting mode of scanning type display module

In the embodiment of the present application, the scanning display module specifically may be: the MEMS scanning mirror or the fiber scanner will be set forth below to set up two types of scanning display modules.

First setting mode of MEMS scanning mirror

Referring to fig. 7a, the optical display module 70 includes: MEMS scanning mirror 701 and optical mirror group 702. In the optical display module 70, when the MEMS scanning mirror 701 is in a static state, a mirror surface of the MEMS scanning mirror 701 is parallel to a mirror plate of the optical lens group 702, and preferably, a center of the mirror surface of the MEMS scanning mirror 701 is coaxial with an optical center of the optical lens group 702. The MEMS scanning mirror 701 and the optical mirror group 702 are collectively disposed obliquely with respect to the surface of the waveguide 200 coupled into the cell 201.

In the view shown in fig. 7a, the specific inclination is: the mirror surface of the MEMS scanning mirror 701 and the optical lens group 702 are closer to the surface of the incoupling unit 201 on the side close to the light exit area of the waveguide 200 in the horizontal direction, while the mirror surface of the MEMS scanning mirror 701 and the optical lens group 702 are farther from the surface of the incoupling unit 201 on the side far from the light exit area of the waveguide 200 in the horizontal direction. Thereby forming the tilted state shown in fig. 7 a.

In such an inclined state, when the MEMS scanning mirror 701 is swept, the image beam S of the left sub-field of view outputted from the optical mirror group 702 after the image beam outputted by scanning passes through the optical mirror group 702₃The image beam S having an incident angle smaller than that of the right sub-field of view is incident on the surface of the coupling-in unit 201₄The angle of incidence to the surface of the incoupling unit 201. It is easy to understand that the scanning angle of MEMS scanning mirror 701 is matched with the size of optical lens group 702, so that the light beam scanned and output by MEMS scanning mirror 701 does not exceed the range of the lens of optical lens group 702.

Second setting mode of MEMS scanning mirror

Fig. 7b shows another arrangement of the optical display module 70, that is, the optical lens group 702 is disposed obliquely with respect to the coupling-in unit 201, and the MEMS scanning mirror 701 is disposed in parallel with respect to the coupling-in unit 201 in the rest state, and preferably, the center of the mirror surface of the MEMS scanning mirror 701 in the rest state is coaxial with the center of the surface of the coupling-in unit 201. The specific inclined arrangement of the optical lens group 702 is similar to the first arrangement, i.e. the optical lens group 702 is closer to the surface of the incoupling unit 201 on the side close to the light exit area of the waveguide 200 in the horizontal direction, and the optical lens group 702 is farther from the surface of the incoupling unit 201 on the side far from the light exit area of the waveguide 200 in the horizontal direction.

Based on the arrangement, when the MEMS scanning mirror 701 scans, the scanned image beam passes through the optical lens group 702, and then the image beam S of the left visual field output from the optical lens group 702 can be made to pass through₃The image beam S having an incident angle smaller than the right field of view on the surface of the incoupling unit 201₄The angle of incidence at the surface of the incoupling unit 201.

Third setting mode of MEMS scanning mirror

Referring to fig. 7c, in the optical display module 70, the MEMS scanning mirror 701 in the resting state is parallel to the mirror plate of the optical lens group 702, and both the MEMS scanning mirror 701 and the optical lens group 702 are parallel to the surface of the coupling-in unit 201. Preferably, the optical axis of the optical lens group 702 is coaxial with the center of the surface of the incoupling unit 201. When the MEMS scanning mirror 701 scans, the image light beams scanned out by the MEMS scanning mirror 701 are asymmetric with respect to the optical lens assembly 702, and specifically, the corresponding scanning area of the image light beams scanned out by the MEMS scanning mirror 701 on the lens of the optical lens assembly 702 does not entirely cover the lens surface of the optical lens assembly 702, but only covers a partial area of the lens surface of the optical lens assembly 702 on the side of the light exiting area of the waveguide 200.

On the basis, after the scanned and outputted image beams pass through the optical lens group 702, the left sub-field and the right sub-field outputted from the optical lens group 702 are asymmetric, so that the image beams S of the left sub-field are made to be asymmetric₃The image beam S having an incident angle smaller than that of the right sub-field of view is incident on the surface of the coupling-in unit 201₄The angle of incidence to the surface of the incoupling unit 201.

First setting mode of optical fiber scanner

Referring to FIG. 8a, the optical display module 80 includes a fiber scanner 801 and an optical lens assembly 802. In the optical display module 80, when the fiber scanner 801 is in a static state, the scanning fiber of the fiber scanner 801 is perpendicular to the lens of the optical lens assembly 802, and preferably, the scanning fiber of the fiber scanner 801 is coaxial with the optical center of the optical lens assembly 802. The fiber scanner 801 and the optical lens group 802 are disposed together obliquely with respect to the surface of the waveguide 200 coupled into the unit 201.

In the view shown in fig. 8a, the specific inclination is: the optical lens group 802 is closer to the surface of the incoupling unit 201 on the side close to the light exit area of the waveguide 200 in the horizontal direction, and the optical lens group 802 is farther from the surface of the incoupling unit 201 on the side far from the light exit area of the waveguide 200 in the horizontal direction. Thereby forming the tilted state shown in fig. 8 a.

Based on the above arrangement, when the optical fiber scanner 801 scans, the scanned image beam can cover the mirror surface of the lens in the optical lens group 802, and the image beam passes through the optical lens group 802, so that the image beam S of the left visual field output from the optical lens group 802 can be obtained₅The image beam S having an incident angle smaller than the right field of view on the surface of the incoupling unit 201₆In the coupling-in unit 201 angle of incidence of the surface.

Second setting mode of optical fiber scanner

Referring to fig. 8b, another arrangement of the optical display module 80 is shown, specifically, the optical lens assembly 802 is disposed obliquely with respect to the coupling-in unit 201, and the scanning fiber of the fiber scanner 801 in the resting state is not perpendicular to the mirror surface of the optical lens assembly 802, but is perpendicular to the surface of the coupling-in unit 201, and preferably, the scanning fiber of the fiber scanner 801 in the resting state is coaxial with the center of the surface of the coupling-in unit 201.

The specific inclined arrangement of the optical lens assembly 802 is similar to the first arrangement, i.e. the optical lens assembly 802 is closer to the surface of the incoupling unit 201 on the side close to the light-exiting region of the waveguide 200 in the horizontal direction, and the optical lens assembly 802 is farther from the surface of the incoupling unit 201 on the side far from the light-exiting region of the waveguide 200 in the horizontal direction.

Based on the arrangement, when the optical fiber scanner 801 scans, the scanned image beam passes through the optical lens assembly 802, and the image beam S of the left visual field output from the optical lens assembly 802 can be made to pass through₅The image beam S having an incident angle smaller than the right field of view on the surface of the incoupling unit 201₆The angle of incidence at the surface of the incoupling unit 201.

Third setting mode of optical fiber scanner

Referring to fig. 8c, in the optical display module 80, the scanning fiber of the fiber scanner 801 in the resting state is perpendicular to the mirror surface of the optical lens assembly 802, and the mirror of the optical lens assembly 802 is parallel to the surface of the incoupling unit 201. Preferably, the optical axis of the scanning fiber of the fiber scanner 801 and the optical lens group 802 is coaxial with the center of the surface of the incoupling unit 201. When the optical fiber scanner 801 scans, the image light beams scanned and outputted by the optical fiber scanner 801 are asymmetric with respect to the optical lens assembly 802, and specifically, the scanning area of the image light beams scanned and outputted by the optical fiber scanner 801 on the lens of the optical lens assembly 802 does not entirely cover the lens surface of the optical lens assembly 802, but only covers a partial area of the lens surface of the optical lens assembly 802 that is biased to the light exit area of the waveguide 200.

On the basis, after the scanned and outputted image beam passes through the optical lens assembly 802, the left sub-field and the right sub-field outputted from the optical lens assembly 802 are asymmetric, so that the image beam S of the left sub-field is made to be asymmetric₅The image beam S having an incident angle smaller than that of the right sub-field of view is incident on the surface of the coupling-in unit 201₆The angle of incidence to the surface of the incoupling unit 201.

Further, referring to fig. 8d, based on the arrangement shown in fig. 8c, the light-exiting end surface of the scanning fiber in the fiber scanner 801 is a slope, and the slope is oriented relative to the area scanned by the fiber scanner 801, in other words, the slope of the light-exiting end surface of the scanning fiber in fig. 8d is oriented towards the right side (i.e. towards the light-exiting area of the waveguide 200). With this structure, the image beam emitted from the scanning fiber can be matched with the arrangement of the fiber scanner 801 in fig. 8c, that is, the image beam scanned and output from the fiber scanner 801 is incident on the partial region of the lens of the optical lens assembly 802 on the light-exiting region side of the deflection waveguide 200.

The above is different arrangement of the optical display module, so as to construct an optical path in which the first side sub-field and the second side sub-field of view in the coupling-in unit 201 of the waveguide 200 are asymmetric. On the basis of the above, it should be noted that, referring to fig. 9a and 9b, the distribution of the light beams in the left and right waveguides corresponding to both eyes is shown. As shown in fig. 9a, in the waveguide 200 corresponding to the left eye, since the incident angle of the image beam of the left sub-field is reduced, the coupling-in angle of the diffracted beam generated after the image beam of the left sub-field passes through the coupling-in unit 201 is further reduced accordingly, and as the diffracted beam is transmitted at a smaller angle in the waveguide 200, the exit angle of the exit beam corresponding to the left sub-field is also smaller when the exit beam is output from the coupling-out unit 202, which may cause the image loss of the left sub-field. As shown in fig. 9b, in the waveguide 200 'corresponding to the right eye, the optical path is symmetrically opposite to that of fig. 9a, that is, the incident angle of the image light beam entering the right sub-field of the coupling-in unit 201' on the waveguide 200 'is smaller than that of the image light beam of the left sub-field, and when the image light beam is output from the coupling-out unit 202', the exit angle of the exit light beam of the right sub-field is also smaller, so that the image of the right sub-field is lost.

Field-of-view tiling

Based on the above embodiments, it can be seen that, due to the adoption of the asymmetric field of view, for a single eye, the field of view of the waveguide output is also asymmetric (refer to fig. 9a and 9b), and in order to further improve the viewing effect, the field of view can be enlarged by adopting the field-of-view splicing manner. Specifically, referring to fig. 10a, a field stitching approach is shown, wherein the

waveguides

200a and 200b may be stacked. Specifically, in fig. 10a, the waveguide 200a is closer to the human eye, the waveguide 200b is disposed outside the waveguide 200a, the field of view output by the waveguide 200a is distributed such that the left sub-field of view is larger than the right sub-field of view, and the field of view output by the waveguide 200b is distributed such that the right sub-field of view is larger than the left sub-field of view. After splicing, the sub-fields of view output by the two waveguides can be mutually compensated.

Referring to fig. 10b, another field stitching approach is shown. Specifically, the waveguide 200 has an integral structure, and the coupling-in units 201a and 201b on the left and right sides share one coupling-out unit 202 corresponding to both eyes (of course, only one eye is shown in fig. 10b for convenience of describing specific parameters of the field of view). In this embodiment, since the splicing manner is adopted, there is a certain requirement for overlapping the view fields according to the exit pupil distance and the exit pupil size. Assuming that the exit pupil distance L is 20mm and the full-field exit pupil diameter D is 10mm, the field angle θ of the overlapping region is_pArctan (D/2L) 14 °. Therefore, it is required that the unilateral minimum field of view incident on the coupling-in unit 201a/201b is not less than 14 °

Further, taking the coupling-in unit 201a as an example, the incident angle of the left sub-field is assumed to be 14 °, and λ is assumed to be 0.52um, n₀＝1，n₁Assuming a diffraction angle of 90 degrees, the grating constant d can be calculated as 313nm (which is already smaller than the currently common grating constant). And supposing that the diffraction angle corresponding to the maximum incidence angle of the right sub-field is the total reflection angle theta of the waveguide_cWhen arcsin (1/n) is 33.7 °, θ is taken_cIf m is 1 at 35 °, the maximum exit angle θ of the right sub-field can be calculated at 41 °. In the same wayThe incidence angles of the left and right sub-fields of the incoupling unit 201b are symmetrically opposite.

It can be seen from the above calculation process that the adoption of the asymmetric field mode in this embodiment can reduce the grating constant and reduce the rainbow effect, and the overall field output range can be increased by asymmetric field splicing.

The embodiments in the present application are described in a progressive manner, and the same and similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from the other embodiments.

Thus, particular embodiments of the present subject matter have been described. Other embodiments are within the scope of the following claims.

The expressions "first", "second", "said first" or "said second" used in various embodiments of the present disclosure may modify various components regardless of order and/or importance, but these expressions do not limit the respective components.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the invention herein disclosed is not limited to the particular combination of features described above, but also encompasses other arrangements formed by any combination of the above features or their equivalents without departing from the spirit of the invention. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims

1. A near-eye display system, comprising at least: an optical display module and a waveguide, wherein,

the optical display module outputs an image light beam;

2. The near-eye display system of claim 1, wherein the optical display module outputs a complete field of view corresponding to the image beam, and an incident angle of the image beam in the first side subfield with respect to the coupling-in unit is smaller than an incident angle of the image beam in the second side subfield with respect to the coupling-in unit; wherein the content of the first and second substances,

3. The near-to-eye display system of any one of claims 1-2, wherein the optical display module comprises at least: an image display module and an optical lens group;

the image display module is used for outputting an image light beam;

4. The near-eye display system of claim 3, wherein the image display module is a panel display module;

5. The near-eye display system of claim 4, wherein a plate surface of the panel-type display module is parallel to the lenses of the optical lens group, and the lenses of the panel-type display module and the optical lens group are together disposed obliquely with respect to a surface of the coupling-in unit of the waveguide.

6. The near-eye display system of claim 4, wherein a face of the panel-type display module is parallel to the incoupling unit surface of the waveguide, and the lenses of the optical lens set are disposed obliquely with respect to the face of the panel-type display module and the incoupling unit surface.

7. A near-eye display system as claimed in claim 5 or 6 wherein the optical lens groups are arranged tilted as follows: in the horizontal direction, the distance from the side of the lens in the optical lens group close to the waveguide light-out region to the surface of the coupling-in unit is smaller than the distance from the side of the lens far away from the waveguide light-out region to the surface of the coupling-in unit.

8. The near-eye display system of claim 3, wherein the image display module is a scanning display module;

9. The near-to-eye display system of claim 8 wherein the scanning display module is a MEMS scanning mirror.

10. The near-eye display system of claim 9, wherein a mirror plate of the MEMS scanning mirror is parallel to a mirror plate of the optical mirror group in a rest state, the mirror plate of the MEMS scanning mirror and the mirror plate of the optical mirror group being disposed together obliquely with respect to a surface of the coupling-in unit of the waveguide;

11. The near-eye display system of claim 9, wherein the mirror plate of the MEMS scanning mirror is parallel to the incoupling unit surface of the waveguide, the mirror plate in the set of optical mirrors being disposed obliquely with respect to the mirror plate of the MEMS scanning mirror and the incoupling unit surface;

12. A near-eye display system as claimed in claim 10 or 11 wherein the optical lens group is tilted in the following manner: in the horizontal direction, the distance from the side of the lens in the optical lens group close to the waveguide light-out region to the surface of the coupling-in unit is smaller than the distance from the side of the lens far away from the waveguide light-out region to the surface of the coupling-in unit.

13. The near-eye display system of claim 9 wherein a mirror plate of the MEMS scanning mirror is parallel to a mirror plate of the optical mirror group in a resting state, and the mirror plate of the optical mirror group is parallel to a surface of the incoupling unit of the waveguide;

14. The near-to-eye display system of claim 8 wherein the scanning display module is a fiber optic scanner.

15. The near-eye display system of claim 14, wherein the scanning fibers of the fiber scanner are perpendicular to the mirror plates of the optical lens group in a rest state, the mirror plates being disposed obliquely with respect to a surface of the incoupling unit of the waveguide;

16. The near-eye display system of claim 14 wherein the scanning fiber of the fiber scanner is perpendicular to the surface of the incoupling unit of the waveguide in a rest state, and the mirror in the optical mirror group is disposed obliquely with respect to the scanning fiber and the surface of the incoupling unit in the rest state;

17. The near-eye display system of claim 15 or 16, wherein the optical lens group is tilted in the following manner: in the horizontal direction, the distance from the side of the lens in the optical lens group close to the waveguide light-out region to the surface of the coupling-in unit is smaller than the distance from the side of the lens far away from the waveguide light-out region to the surface of the coupling-in unit.

18. The near-eye display system of claim 14 wherein the scanning fibers of the fiber optic scanner are perpendicular to the optic of the optical lens assembly in the resting state, and wherein the optic of the optical lens assembly is parallel to the incoupling unit surface of the waveguide;

19. The near-eye display system of claim 18, wherein the light exit end of the scanning fiber is beveled.

20. The near-eye display system of claim 1, wherein the number of the optical display modules is two, and the two optical display modules are respectively used for outputting image beams corresponding to two eyes.

21. The near-eye display system of claim 20, wherein the waveguide is at least two stacked waveguides, the image beams with asymmetric viewing fields output by the two optical display modules are respectively input into the two stacked waveguides, and the image beams output by the stacked waveguides are input into the human eye after being subjected to viewing field splicing.

22. The near-eye display system of claim 20, wherein the waveguide is an integrated waveguide including two left and right coupling-in units and a common coupling-out unit, wherein the image beams with asymmetric viewing fields output by the two optical display modules are input into the waveguide from the two left and right coupling-in units respectively, and the image beams are output to human eyes after being field-spliced by the common coupling-out unit.