CN218298669U - Near-to-eye display device - Google Patents

Abstract

The utility model discloses a near-to-eye display device, diffraction light waveguide that this near-to-eye display device includes include the waveguide basement and set up the coupling-in area and the coupling-out area in at least one side of waveguide basement, the light beam that the ray apparatus throws transmits to the coupling-out area through the total reflection in the coupling-in area coupling-in waveguide basement, the second coupling-out area of coupling-out area includes a plurality of coupling-out subregions, the grating direction of the one-dimensional grating of filling in setting up two at least coupling-out subregions is different, satisfy the light beam through the second coupling-out regional pupil expansion and coupling-out; the one-dimensional grating filled in the first coupling-out region of the coupling-out region has the same grating vector as the one-dimensional grating in the coupling-out sub-region, so that the coupling-out energy at the edge is increased and compensated, and the imaging effect of the near-eye display device is improved.

Description

Near-to-eye display device

This application claims priority from the chinese patent office filed on 29/04/2022, application number 2022211037796, which is incorporated herein by reference in its entirety.

Technical Field

The embodiment of the utility model provides a relate to and show technical field, especially relate to a near-to-eye display device.

Background

Augmented Reality (AR) is a technology for merging real world and virtual information, and an optical waveguide system is one of key components for implementing AR technology. In a display scene for augmented reality, an optical machine is required to project an image light beam which is required to be superimposed on a real scene onto an optical waveguide system, and the optical waveguide system deflects the transmission direction of the image light beam, so that the image light beam enters human eyes.

An optical waveguide system in an existing near-eye display device generally adopts a one-dimensional grating for pupil expansion and outcoupling, however, the grating layout of the optical waveguide system is divided into an obvious pupil expansion grating and an obvious outcoupling grating, which brings about the disadvantage that the design of the appearance of the near-eye display device is affected by the existence of a pupil expansion structure, and the design of a lens of the near-eye display device is usually required to be designed to be very large, so that the appearance is affected. In comparison, the two-dimensional diffractive waveguide only has one coupling-in structure and one coupling-out structure, and the two-dimensional grating of the coupling-out structure can realize the effects of pupil expanding and coupling-out simultaneously, so that the appearance design of the glasses adopting the two-dimensional diffractive waveguide is relatively more flexible. On one hand, however, the preparation process of the two-dimensional grating is relatively more complex, and the precision requirement is higher; on the other hand, the efficiency of the grating is far lower than that of a one-dimensional grating because of the multiple diffraction orders, so that a large amount of energy is wasted.

Disclosure of Invention

In view of this, the embodiment of the utility model provides a near-to-eye display device, through when designing this near-to-eye display device's diffraction light waveguide, divide into a plurality of coupled-out subregions with the coupled-out subregion with the different one-dimensional grating of grating direction, adopt the one-dimensional grating to replace the two-dimensional grating, realize the pupil expanding and the coupled-out of light beam, and obtain higher diffraction efficiency, effectively improved the visual imaging effect of diffraction optical waveguide on the basis of the design of the glasses appearance of relative excellence like this, the experience of wearing of near-to-eye display device has been promoted.

The embodiment of the utility model provides a near-to-eye display device, include:

an apparatus main body;

a light engine for projecting a light beam and provided in the apparatus main body; and

a diffractive optical waveguide that is provided in the apparatus body and includes a waveguide substrate and a coupling-in area and a coupling-out area that are provided on at least one side of the waveguide substrate;

the waveguide substrate is provided with a first surface and a second surface which are parallel to each other, and the coupling-in area is used for coupling light beams into the waveguide substrate so that the light beams are transmitted to the coupling-out area in a total reflection mode between the first surface and the second surface; the coupling-out region comprises a first coupling-out region and a second coupling-out region; the second coupling-out region comprises a plurality of coupling-out sub-regions, at least two kinds of one-dimensional gratings with different grating directions are arranged in the second coupling-out region, one kind of one-dimensional gratings with at least two different grating directions is arranged in each coupling-out sub-region, and the second coupling-out region is used for expanding the pupil of the light beam and coupling out the waveguide substrate in a diffraction mode; the grating vector of the one-dimensional grating arranged in the first coupling-out region is the same as that of one of the one-dimensional gratings in the coupling-out sub-region; the first outcoupling region is for diffractively outcoupling the light beam out of the waveguide substrate.

The utility model provides a near-to-eye display device, diffraction light waveguide that it includes divide the coupling region and include first coupling region and second coupling region, continue to divide the second coupling region and include a plurality of coupling subregions, fill the one-dimensional grating of a grating direction in each coupling subregion, set up the grating direction difference of the one-dimensional grating in at least two coupling subregions, satisfy the light beam through the second coupling region expand pupil and coupling out; meanwhile, the grating vectors of the one-dimensional grating filled in the first coupling-out area and the one-dimensional grating in the coupling-out sub-area are set to be the same, so that the effect of increasing the coupling-out of edge light rays and compensating the coupling-out energy at the edge is achieved, light beams projected by the optical machine are coupled into the waveguide substrate from the coupling-in area and are transmitted to the coupling-out area, the area corresponding to the coupling-in area in the coupling-out area, namely the second coupling-out area, can realize pupil expansion and coupling-out, and the edge area of the coupling-out area, namely the first coupling-out area, realizes coupling-out, so that higher diffraction efficiency is obtained, and coupling-out uniformity is facilitated.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

fig. 1 is a schematic diagram of a near-eye display device according to an embodiment of the present invention;

fig. 2 is a schematic plan view of a diffractive light waveguide according to an embodiment of the present invention;

FIG. 3 is a schematic perspective view of the diffractive light waveguide shown in FIG. 2;

FIG. 4 is a (K-space) wave vector space diagram of the light beam of FIG. 3;

fig. 5 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention;

fig. 6 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention;

fig. 7 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention;

fig. 8 is a schematic diagram of a coupling-out subregion provided by an embodiment of the present invention;

fig. 9 is a schematic diagram of another coupling-out subregion provided by an embodiment of the present invention;

fig. 10 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention;

fig. 11 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention;

fig. 12 is a schematic diagram of another coupling-out subregion provided by an embodiment of the present invention;

fig. 13 is a schematic diagram of another coupling-out subregion provided in the embodiment of the present invention.

Fig. 14 is a schematic diagram of another outcoupling sub-region provided by an embodiment of the present invention;

fig. 15 is a schematic diagram of another coupling-out subregion provided by an embodiment of the present invention;

fig. 16 is a schematic diagram of another coupling-out subregion provided by the embodiment of the present invention;

fig. 17 is a schematic diagram of a coupling-out region according to an embodiment of the present invention;

fig. 18 is a schematic diagram of another outcoupling region provided by an embodiment of the present invention;

fig. 19 is a schematic diagram of another outcoupling region provided by the embodiment of the present invention;

fig. 20 is a schematic diagram of another outcoupling region provided by an embodiment of the present invention;

fig. 21 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention;

fig. 22 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail through the following embodiments with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, not all embodiments, and all other embodiments obtained by those skilled in the art without creative efforts based on the embodiments of the present invention all fall into the protection scope of the present invention.

The utility model provides a near-to-eye display device, this near-to-eye display device include equipment main part, ray apparatus and diffraction light waveguide. The diffraction light guide comprises a waveguide substrate, the waveguide substrate is provided with a first surface and a second surface which are parallel to each other, and a coupling-in area and a coupling-out area are arranged on the first surface and/or the second surface. The coupling-in area is used for coupling the light beam projected by the optical machine into the waveguide substrate so that the light beam is transmitted to the coupling-out area in a total reflection manner between the first surface and the second surface of the waveguide substrate; the coupling-out region comprises a first coupling-out region and a second coupling-out region; the second coupling-out area comprises a plurality of coupling-out subareas, at least two one-dimensional gratings with different grating directions are arranged in the second coupling-out area, the one-dimensional grating arranged in each coupling-out subarea is one of the at least two one-dimensional gratings with different grating directions, and the second coupling-out area is used for expanding the pupil of the light beam and coupling out the waveguide substrate in a diffraction mode; the grating vectors of the one-dimensional grating arranged in the first coupling-out region are the same as the grating vectors of one of the one-dimensional gratings in the coupling-out sub-region; the first outcoupling region serves to couple the light beam out of the waveguide substrate by means of diffraction. Preferably, the sum of the grating vectors of the one-dimensional gratings in the in-coupling region and the out-coupling region is zero.

Exemplarily, fig. 1 is a schematic diagram of a near-eye display device provided by an embodiment of the present invention. As shown in fig. 1, the near-eye display device may include an optical engine 4 for projecting a light beam, a device body, and a diffractive optical waveguide, wherein the optical engine 4 and the diffractive optical waveguide are correspondingly disposed in the device body, such that after the light beam provided via the optical engine is diffraction-coupled into the diffractive optical waveguide by a grating structure in a coupling-in area 2, the coupled-in light propagates in the diffractive optical waveguide to a coupling-out area 3 to be uniformly coupled out by the grating structure disposed in the coupling-out area 3 to be received by a user's eye to see a corresponding image. More specifically, as shown in fig. 1, the apparatus body of the near-eye display apparatus may be implemented as an eyeglass frame including a rim 5 and two temples 6 respectively extending rearward from left and right sides of the rim, the optical engine 4 being provided in the apparatus body eyeglass frame, the diffractive optical waveguide being provided in the rim implemented as a display lens on which the coupling-in area 2 and the coupling-out area 3 are provided.

Specifically, the grating direction is a direction in which the grating units are periodically arranged. The propagation direction of the grating after diffraction is related to the grating direction, and the one-dimensional gratings with at least two different grating directions are arranged in the second coupling-out area, so that the light beam can be deflected to propagate in at least two directions in the second coupling-out area through diffraction, the pupil expansion of the light beam can be effectively realized, and the uniformity of the pupil expansion can be further improved. The one-dimensional grating in the first outcoupling region has the same grating vector as one of the one-dimensional gratings in the outcoupling sub-regions in order to allow efficient outcoupling of the light beam propagating from the second outcoupling region.

Since non-monochromatic light is diffracted by the grating, chromatic dispersion is generated, and the chromatic dispersion affects the imaging effect. In some embodiments, the light beam emitted by the optical machine enters the human eye after being diffracted by the grating in the coupling-in area and the grating in the coupling-out area, and when the sum of the grating vectors of the one-dimensional gratings in the coupling-in area and the coupling-out area is zero, the chromatic dispersion generated by multiple diffraction of the light beam before entering the human eye can be offset. In other embodiments, the dispersion caused by diffraction can be compensated by other methods or structures, so that the picture viewed by the user has no dispersion.

Fig. 2 is a schematic plan view of a diffractive light waveguide according to an embodiment of the present invention; FIG. 3 is a schematic perspective view of a diffractive light waveguide shown in FIG. 2; fig. 4 is a (K-space) wave vector space diagram of the light beam of fig. 3. As shown in fig. 2 to 3, the diffractive light waveguide includes a waveguide substrate 1, the waveguide substrate 1 having a first surface M1 and a second surface M2 parallel to each other, a coupling-in area 2 and a coupling-out area 3 provided on the first surface M1 of the waveguide substrate 1; the coupling-in area 2 is used for coupling the light beam projected by the optical machine into the waveguide substrate 1, so that the light beam is transmitted to the coupling-out area 3 by total reflection between the first surface M1 and the second surface M2; the coupling-out region 3 comprises a first coupling-out region 31 and a second coupling-out region 32; the second coupling-out region 32 includes a plurality of coupling-out subregions 321, a one-dimensional grating is disposed in each coupling-out subregion 321, the grating directions of the one-dimensional gratings in at least two coupling-out subregions 321 are different, and the second coupling-out region 32 is configured to expand the pupil of the light beam and couple out the waveguide substrate 1 in a diffraction manner; the one-dimensional grating in the first coupling-out region 31 has the same grating vector as the one-dimensional grating in the coupling-out sub-region 321; the first outcoupling region 31 serves to couple the light beam out of the waveguide substrate 1 by means of diffraction.

Illustratively, the waveguide substrate 1 may be optical glass, the thickness of the waveguide substrate 1 is between 0.5mm and 3mm, and the length of the waveguide substrate 1 may be set according to the needs of the actual scene. One-dimensional gratings, such as straight-tooth gratings, blazed gratings, skewed-tooth gratings, volume holographic gratings, and the like, are arranged in the coupling-in region 2 and the coupling-out region 3.

It should be noted that, in order to avoid the complicated process caused by using the two-dimensional grating, the coupling-in region and the coupling-out region of the present application both use the one-dimensional grating structure. In order to realize a larger field angle and better viewing experience, the pupil needs to be fully expanded in the coupling-out area, the coupling-out area is partitioned according to the relative position relationship between the coupling-in area and the coupling-out area, the first coupling-out area and the second coupling-out area are partitioned, and the one-dimensional grating is arranged according to the pupil expanding requirements of different partitions. Specifically, for a region (second coupling-out region) of the coupling-out region corresponding to the coupling-in region, since most of the light beams coupled in from the coupling-in region and propagating directly enter the second coupling-out region, and most of the energy of the light beams is concentrated in the part of the light beams, the present application divides the region into a plurality of coupling-out sub-regions by further partitioning the region, in which at least two different directions of one-dimensional gratings are disposed, and one-dimensional grating is disposed in each coupling-out sub-region, so that the light beams propagating from the coupling-in region can be expanded and coupled out toward one side or both sides. For the first coupling-out region, the light sources are mainly the boundary field light beams and the expanded light beams from the second coupling-out region, and the energy of the light is less, so that the expanded pupil needs to be reduced to increase coupling-out, and the coupling-out energy at the edge needs to be compensated, so that the sub-region division is not performed, and only one-dimensional grating needs to be filled.

Referring to fig. 2, the light beam incident on the first coupling-out region 31 is mainly a pupil-expanded light beam from the second coupling-out region 32, and since the energy remaining in the waveguide substrate 1 after each diffraction coupling-out is reduced, the energy obtained at the boundary region between the first coupling-out region 31 and the second coupling-out region 32 is already small, and at this time, the pupil expansion needs to be reduced to increase the coupling-out, the coupling-out energy at the edge needs to be compensated, and the first coupling-out region 31 is not sub-divided, and only a one-dimensional grating needs to be filled. Meanwhile, through parameter optimization setting, the sum of the grating vector of the one-dimensional grating in the coupling-in area 2 and the grating vector of the one-dimensional grating in the coupling-out area 3 is zero, light can be coupled out of the waveguide substrate 1 without dispersion and enter eyes of a user, and the one-dimensional grating is adopted to replace a two-dimensional grating, so that higher diffraction efficiency can be obtained. Wherein S is an incident beam and S' is an exit beam coupled through the expanding pupil of the waveguide substrate 1.

With reference to fig. 2 to 4, a schematic diagram of a light transmission process in k-space is shown, and the setting of different grating vectors of the one-dimensional gratings in at least two outcoupling sub-regions 321 enables simultaneous pupil expansion and outcoupling in the outcoupling region 3, where the wave vector space diagram in fig. 4 is a two-dimensional projection of three-dimensional k-space, and the Z-direction component is omitted. Taking an incident beam as a rectangular beam as an example, a rectangular frame in the k-space shown in fig. 4 is represented as a field of view, and any point in the rectangular frame corresponds to a field of view

The incident light. Referring to FIGS. 2 and 4, the incident beam S is coupled into the waveguide substrate 1 by the grating diffraction Kin1 and Kin2, and Kin2 component propagates in the positive Y-axis direction to become a useful beam. When the Kin2 component is incident on the outcoupling grating 41 (or outcoupling grating 42) in the second outcoupling region 32, the Kout11 component diffracted by the outcoupling grating 41 (or outcoupling grating 42) continues to propagate in the ring in the positive X-axis direction in the waveguide (actually does not exist); or diffraction of the Kout21 component by the outcoupling grating 42 continues in the ring propagating in the waveguide substrate 1 in the positive X-direction(actually not present), when the Kout11 component enters the outcoupling grating 41 (or outcoupling grating 42), the Kout21 component is diffracted by the outcoupling grating 41 (or outcoupling grating 42) and continues to propagate in the waveguide in the positive Y-axis direction (actually not present) within the ring; or coupling out the waveguide (actually not present) within the inner circle by diffracting the Kout21 component through the coupling-out grating 42. The above example fills the outcoupling region 3 with 2 kinds of outcoupling gratings, but is not limited thereto.

To sum up, the utility model provides a diffraction light waveguide includes the waveguide basement and sets up the coupling-in area and the coupling-out area in waveguide basement one side, the transmission of total reflection between the relative two surfaces that set up of waveguide basement in the light beam that the ray apparatus throws is to the coupling-out area through the coupling-in area coupling-in waveguide basement, divide the coupling-out area to include first coupling-out area and second coupling-out area, continue to divide the second coupling-out area to include a plurality of coupling-out subareas, the one-dimensional grating of a kind of grating vector is filled in every coupling-out subarea, the grating vector of the one-dimensional grating in setting up at least two coupling-out subareas is different, satisfy the light beam through second coupling-out area expanding pupil and coupling-out waveguide basement; meanwhile, the grating vectors of the one-dimensional grating filled in the first coupling-out area and the one-dimensional grating in the coupling-out sub-area are set to be the same, so that the effects of increasing the coupling-out of edge light and compensating the coupling-out energy at the edge are achieved, the sum of the grating vectors of the one-dimensional grating in the coupling-in area and the grating vectors of the one-dimensional grating in the coupling-out area is further set to be zero, the light beam is coupled out without dispersion, and the visual imaging effect of the diffraction optical waveguide is effectively improved.

On the basis of the above embodiment, the division of the second coupling-out area into a plurality of coupling-out sub-areas may be regular partitions or irregular partitions, that is, random partitions.

In some embodiments, the second coupling-out region is a regular partition, and the shape of each of the remaining coupling-out sub-regions is the same except for the coupling-out sub-regions located on the boundary of the second coupling-out region. Or, when the second coupling-out region is a regular partition, the second coupling-out region is regularly divided into a plurality of coupling-out sub-regions along one direction, or the second coupling-out region is regularly divided into a plurality of coupling-out sub-regions along two different directions.

In this application, the second coupling-out region may be divided into a plurality of coupling-out sub-regions along one direction, and the grating directions of the one-dimensional gratings in two adjacent coupling-out sub-regions are different. The sizes of the plurality of coupling-out subregions in the direction are random, but the maximum size of each coupling-out subregion in the direction is smaller than the spot size of a light beam incident on the coupling-out subregion, and the central distance between two adjacent coupling-out subregions is larger than or equal to lambda/nsin theta; wherein n is the refractive index of the waveguide substrate, θ is the minimum angle distinguishable by human eyes, and λ is the wavelength of the light beam projected by the optical machine. Therefore, pupil expansion can be effectively realized through division of the coupling-out sub-regions and grating distribution, the distance between adjacent diffraction orders can be beyond the discrimination capability of human eyes and can not be directly felt by the human eyes, the problem of multiple diffraction orders is effectively avoided and reduced, and the display image definition of the diffraction light waveguide is improved.

Exemplarily, fig. 5 is a schematic plane structure diagram of another diffractive optical waveguide provided in an embodiment of the present invention; fig. 6 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention; fig. 7 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention. It can be seen that fig. 5 illustrates the second coupling-out region divided into a plurality of coupling-out sub-regions in the Y direction, and one-dimensional gratings B and one-dimensional gratings C are respectively filled in the coupling-out sub-regions 321 along the Y direction in the figure to form an arrangement of B, C, B, C \8230 \ 8230: \, 8230:, so that the grating directions of the one-dimensional gratings in two adjacent coupling-out sub-regions are different. Fig. 6 shows an arrangement manner of a one-dimensional grating a, a one-dimensional grating B, and a one-dimensional grating C respectively filled in each coupling-out sub-region 321 along the X direction in the figure to form a grating direction of a grating 8230, and a grating direction of a grating in two adjacent coupling-out sub-regions are different. Fig. 7 shows a direction deviating from the Y direction by a certain angle in the X direction to divide the second outcoupling region into a plurality of outcoupling sub-regions, and the grating directions of the one-dimensional gratings in two adjacent outcoupling sub-regions in this direction are different.

It should be noted that the regular division in the above example means that the shapes of the sub-regions are consistent, such as triangles, quadrangles, zigzag shapes, and the like, but the size is not required to be consistent. For example, the coupling-out sub-regions are regularly divided into quadrilateral shapes, where it is not required that each sub-region has exactly the same size, and the shape of each coupling-out sub-region is quadrilateral except for the coupling-out sub-regions at the boundary of the second region, where another shape may exist.

In this application, the second coupling-out region may be divided into a plurality of coupling-out sub-regions along two directions, and the grating directions of the one-dimensional gratings in two adjacent coupling-out sub-regions are different. The size constraint of the outcoupling sub-regions is the same as that of the outcoupling sub-regions divided in one direction. Optionally, in this division, the coupling-out sub-regions are identical in shape except for the coupling-out sub-regions located on the boundary of the second coupling-out region.

Exemplarily, referring to fig. 2, the second coupling-out region is regularly divided into a plurality of coupling-out subregions 321 in the X and Y directions, and the remaining coupling-out subregions are rectangular in shape except for the coupling-out subregions located on the boundary of the second coupling-out region. The shape of the outcoupling sub-region 321 may also be other regular shapes, such as a hexagon (as shown in fig. 8) or a triangle (as shown in fig. 9), etc.

Fig. 10 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention; fig. 11 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention. Referring to fig. 10 and 11, the second coupling-out area is also regularly divided into a plurality of coupling-out sub-areas 321 in two directions. As shown in fig. 10, the coupling-out sub-region 321 in the center of the second coupling-out region 32 is a diamond shape, the coupling-out sub-regions 321 are sequentially nested and divided in the dividing direction of the two side edges of the diamond shape, the widths d0 of the coupling-out sub-regions 321 may be the same or different, one-dimensional gratings are filled in the coupling-out sub-regions 321, and two adjacent coupling-out sub-regions 321 are different, such as one-dimensional gratings B and one-dimensional gratings C are respectively filled in the coupling-out sub-regions 321. When the light one-dimensional grating B acts, the light is diffracted, the + 1-order light deflects towards the second sub-coupling-out region 312 for propagation, the 0-order light continues to keep the original direction for propagation, until the one-dimensional grating C acts, the-1-order light is generated, the light deflects towards the first sub-coupling-out region 311 for propagation, the 0-order light continues to keep the original direction for propagation, and the steps are repeated. The deflected +1 and-1 order light rays will interact with the one-dimensional grating B and the one-dimensional grating C during propagation, thereby generating outcoupled light rays. Particularly, the one-dimensional grating a can also exist in the middle area of the second coupling-out area, and the 0-order grating and the one-dimensional grating a can be directly coupled out, so that the efficiency under the field of view is improved. It should be noted that the figure only schematically shows the filling of one-dimensional gratings in several coupling-out sub-regions 321, and the filling manner of other coupling-out sub-regions 321 is not shown.

The manner of regularly partitioning the second coupling-out region is not limited to the manner described in the present application, and any manner that can regularly partition the second coupling-out region is included.

It should be noted that, when the second coupling-out region is designed in a regular partition manner, a periodically arranged structure is formed by taking the coupling-out sub-regions as units, the structure may have a problem of multiple diffraction orders, and the size of the coupling-out sub-regions is reasonably set to meet the requirement that the center distance between two adjacent coupling-out sub-regions is greater than or equal to d ≧ λ/nsin θ, so that the distance between two adjacent diffraction orders can be beyond the discrimination capability of human eyes and can not be directly felt by the human eyes, the problem of multiple diffraction orders can be effectively avoided and reduced, and the definition of a display image of the diffraction light waveguide is improved.

In some embodiments, when the second coupling-out region is a regular partition, each coupling-out sub-region may further include at least two coupling-out secondary sub-regions, and the grating directions of the coupling-out secondary sub-regions are different from each other.

Exemplarily, fig. 12 is a schematic diagram of another coupling-out subregion provided by the embodiment of the present invention; fig. 13 is a schematic diagram of another coupling-out sub-region provided in the embodiment of the present invention. Each coupling-out subregion 321 includes a plurality of coupling-out secondary subregions 3211, and the raster vector directions of the coupling-out secondary subregions 3211 are different from each other. Specifically, as shown in fig. 12 and 13, for the second coupling-out area 32 after the first partitioning, a plurality of coupling-out secondary sub-areas 3211 can be obtained by continuously partitioning in each coupling-out sub-area 321. For example, in fig. 12, the central region of the coupling-out sub-region 321 with the rectangular specification is divided into coupling-out two-stage sub-regions 3211, and in fig. 13, when the coupling-out sub-regions 321 with the hexagonal specification are equally divided into coupling-out two-stage sub-regions 3211, when filling one-dimensional gratings in the plurality of coupling-out two-stage sub-regions 3211, only one-dimensional gratings with different grating vectors need to be filled in the plurality of coupling-out two-stage sub-regions 3211 in each coupling-out sub-region 321, so that the grating vectors of the one-dimensional gratings in two adjacent coupling-out two-stage sub-regions 3211 are different, thereby realizing pupil expansion and coupling-out of the light beam.

In some embodiments, the second outcoupling region is an irregular partition, i.e., a random partition. The second coupling-out region is an irregular partition, and at least two coupling-out sub-regions in the rest coupling-out sub-regions have different shapes except for the coupling-out sub-regions on the boundary of the second coupling-out region. When the optical fiber is divided irregularly, the coupling-out subregions are not arranged periodically any more, so that the problem of multi-order diffraction can be avoided or reduced, and no additional limitation on the lower limit of the size is needed.

On the basis of the above embodiment, optionally, when the second coupling-out region is an irregular partition, the coupling-out sub-region is a thiessen polygonal partition; wherein the discrete points dividing the Thiessen polygon partition are intersection points of the light beams coupled into the optical waveguide substrate and the second coupling-out area; and/or offsetting the derived offset point based on the reference point of the initial coupled-out sub-region of the regular partition.

Fig. 14 is a schematic diagram of another coupling-out sub-region provided in the embodiment of the present invention. Referring to fig. 14, it is possible to optimize the partition design by partitioning the thiessen polygon according to von roulen diagrams (Voronoi diagrams) on the basis of regular patterns, and break the periodic arrangement of the coupling-out sub-regions in the case of regular partitions to avoid the multi-order diffraction problem. In another embodiment, when the second coupling-out region is an irregular partition, the target points for partitioning the thiessen polygon may be selected by optical path tracing. A group of vertical bisectors of line segments connecting any two adjacent target points are determined based on the target points, a plurality of coupling-out sub-regions 321 are divided in the second coupling-out region, one-dimensional gratings with different grating vectors are filled in the same manner as regular rectangular partitions, the second coupling-out region 32 of the irregular partition is formed, and the diffraction problems of multiple diffraction orders of the expanded pupil and the coupled-out light can be effectively avoided or reduced.

The manner of irregularly partitioning the second coupling-out region is not limited to the manner described in the present application, and any manner that can irregularly partition the second coupling-out region is included.

In some embodiments, the second outcoupling region comprises a dimension of each outcoupling sub-region in at least one direction that is smaller than the spot size of the light beam. Optionally at least smaller than the spot size of the light beam reaching the second outcoupling region.

Exemplarily, as shown in fig. 2, 5, 6, 7, 10, and 11, the size d0 of each coupling-out sub-region 321 in at least one direction is smaller than the spot size of the light beam a' reaching the second coupling-out region 32, so as to ensure that all light beams on the gratings in different vector directions are diffracted to expand the pupil.

In some embodiments, at least three one-dimensional gratings with different grating directions are disposed in the second coupling-out region, and a first one-dimensional grating in the one-dimensional gratings is the same as the one-dimensional grating disposed in the coupling-in region; in the coupling-out sub-region of the second coupling-out region, a dimension in at least one direction of the coupling-out sub-region filling the first one-dimensional grating is smaller than a dimension in the direction of the coupling-out sub-region filling the remaining one-dimensional gratings of the one-dimensional gratings.

It can be understood that the first one-dimensional grating is the same as the one-dimensional grating of the coupling-in area, when the light beam enters the coupling-out area provided with the first one-dimensional grating, the light beam can be deflected to be directly coupled out, the coupling-out efficiency is high, and thus the coupling-out efficiency can be improved by locally arranging the first one-dimensional grating in the coupling-out area. Therefore, in the present application, the dimension in at least one direction of the coupling-out sub-region filling the first one-dimensional grating is set to be smaller than the dimension in the direction of the coupling-out sub-region filling the remaining one-dimensional gratings in the one-dimensional gratings, so as to balance the coupling-out efficiency and the uniformity.

Fig. 15 schematically illustrates a second coupling-out region partition and a filling one-dimensional grating in an embodiment of the present application, and fig. 16 schematically illustrates the second coupling-out region partition and the filling one-dimensional grating in an embodiment of the present application. Referring to fig. 15, the coupling-out sub-region 321 (03) is filled with a first one-dimensional grating which is the same as the one-dimensional grating of the coupling-in grating, the coupling-out sub-region 321 (01) and the coupling-out sub-region 321 (02) are provided with one-dimensional gratings different from the coupling-in grating, and the size of the coupling-out sub-region 321' in the X direction is smaller than the size of the coupling-out sub-region 321 (01) and the coupling-out sub-region 321 (02) in the X direction. Referring to fig. 16, the coupling-out sub-region 321 (06) and the coupling-out sub-region 321 (07) are filled with a first one-dimensional grating which is the same as the coupling-in grating, the coupling-out sub-region 321 (04) and the coupling-out sub-region 321 (05) are provided with one-dimensional gratings different from the coupling-in grating, the sizes of the coupling-out sub-region 321 (06) in the Y direction and the X direction are respectively smaller than the sizes of the coupling-out sub-region 321 (04) and the coupling-out sub-region 321 (05) in the Y direction and the size of the coupling-out sub-region 321 (07) in the Y direction are respectively smaller than the sizes of the coupling-out sub-region 321 (04) and the coupling-out sub-region 321 (05) in the Y direction.

On the basis of the above embodiment, the second coupling-out region includes a first side and a second side that are oppositely arranged; the first side edge is close to the coupling-in area; the length of the first side edge is greater than that of the second side edge, and the width of the second coupling-out region is gradually reduced along the first direction; the first direction is a direction in which the first side faces the second side, and the width of the second coupling-out region is a length in a second direction perpendicular to the first direction.

It should be noted that the second coupling-out region includes a first side and a second side that are oppositely disposed; the first side edge is close to the coupling-in area; the first direction is defined as a direction in which the first side faces the second side, and the width of the second coupling-out region is defined as a length in a second direction perpendicular to the first direction. The grating structure of the second coupling-out area is used for expanding the light beam to one side or two sides, coupling the light beam out of the waveguide substrate and continuously attenuating the light energy expanded to one side or two sides, so that the length of the first side edge of the second coupling-out area is larger than that of the second side edge, and the width of the second coupling-out area is gradually reduced along the first direction, so that the coupling-out uniformity is improved.

Fig. 17 is a schematic diagram of a coupling-out region according to an embodiment of the present invention; fig. 18 is a schematic diagram of another outcoupling region provided by the embodiment of the present invention; fig. 19 is a schematic diagram of another outcoupling region provided by the embodiment of the present invention; fig. 20 is a schematic diagram of another coupling-out area according to an embodiment of the present invention, and fig. 21 is a schematic diagram of another coupling-out area according to an embodiment of the present invention. Referring to fig. 17-21, optionally, the second coupling-out region 32 includes a first side L1 and a second side L2 disposed oppositely; the first side L1 is close to the coupling-in region 2; the length of the first side L1 is greater than the length of the second side L2, and the width H1 of the second coupling-out region 32 gradually decreases along the first direction.

It can be understood that the energy carried by the light beam is attenuated as the light beam propagates and diffracts, and the energy is lower the farther away from the coupling-in region, so that the number of pupil expansion actions needs to be reduced, the number of coupling-out actions needs to be increased, and the coupling-out energy at the edge needs to be compensated. Therefore, it is preferable that the first sub-coupling-out region 311 and the second sub-coupling-out region 312 are configured to gradually increase in size as being away from the coupling-in region, for example, the length of the first side L1 is configured to be greater than the length of the second side L2, so that the width H1 of the second coupling-out region 32 gradually decreases along the direction in which the first side L1 points to the second side L2. On the basis of the above embodiment, the length of the first side edge satisfies the boundary condition that the boundary field angle light emitted by the optical machine reaches the second coupling-out region. This prevents the incident light from entering the first coupling-out region without passing through the diffractive pupil of the second coupling-out region, which may result in the light not being effectively coupled out.

Fig. 22 is a schematic plan view of another diffractive optical waveguide according to an embodiment of the present invention. Referring to fig. 17-22, optionally, the length of the first side L1 satisfies a boundary condition that the boundary field angle light ray (101) emitted from the optical engine reaches the second coupling-out region 32.

Alternatively, as shown in fig. 17 to fig. 22, the grating depth of the one-dimensional grating gradually becomes deeper along the direction from the first side L1 to the second side L2. Besides grating partition, the height of the one-dimensional grating can be further partitioned, the principle that the depth of the grating gradually becomes deeper along the direction far away from coupling is followed, and the improvement of the diffraction efficiency of the grating is facilitated. Wherein, the grating depth is 10nm-200nm, and the numerical value can be continuous or discrete.

On the basis of the above embodiment, the second coupling-out region further includes a third side; the third side is an area boundary edge of the first coupling-out area and the second coupling-out area; the third side is one or more of straight side, curved side and zigzag side.

Specifically, the second coupling-out region is a region of the coupling-out region corresponding to the coupling-in region. The distribution of the first coupling-out areas is related to the position relationship between the coupling-in areas and the coupling-out areas. When the coupling-in region deviates to one side of the coupling-out region, the first coupling-out region may be distributed only on one side of the second coupling-out region. When the coupling-in region is not deviated to one side of the coupling-out region, the first coupling-out region is distributed on two sides of the second coupling-out region, namely, the first sub-coupling-out region and the second sub-coupling-out region. In addition, the widths of the first sub-coupling-out region and the second sub-coupling-out region are also related to the position relationship between the coupling-in region and the coupling-out region. When the central axes of the coupling-in area and the coupling-out area in the first direction are consistent, the first sub-coupling-out area and the second sub-coupling-out area are symmetrically arranged around the central axis; when the coupling-in region deviates from the central axis of the coupling-out region in the first direction, the widths of the first sub coupling-out region and the second sub coupling-out region are different, and the width of the first sub coupling-out region closer to the coupling-in region is larger than the width of the second sub coupling-out region.

As shown in fig. 17-21, optionally, the second coupling-out area 32 further includes a third side L3 disposed oppositely, where the third side L3 is an area boundary of the first coupling-out area 31 and the second coupling-out area 32; the third side L3 is one or more of straight side, curved side and zigzag side. The first coupling-out area 31 is gradually increased along the direction from the first side L1 to the second side L2, so as to reduce the pupil expansion action times, increase the coupling-out action times, compensate the coupling-out energy at the edge, and improve the light energy distribution uniformity of the emergent light field of the diffractive light waveguide coupling-out area. In fig. 21, when the coupling-in region is deviated to one side of the coupling-out region, the first coupling-out region may be distributed to one side of the second coupling-out region. In fig. 17-20, when the coupling-in region is not deviated to one side of the coupling-out region, the first coupling-out region is distributed on two sides of the second coupling-out region, including the first sub-coupling-out region and the second sub-coupling-out region.

On the basis of the above embodiment, optionally, the grating depths of the one-dimensional gratings in the first coupling-out region and the second coupling-out region respectively gradually increase along the direction away from the coupling-in region.

Specifically, the grating has grating parameters: n is the refractive index of the material of the waveguide substrate, gamma is the tilt angle of the grating, lambda is the grating period, W is the grating width, and H is the grating depth. The grating depths H of the one-dimensional gratings in the first coupling-out area 31 and the second coupling-out area 32 are gradually increased along the direction far away from the coupling-in area, so that the diffraction efficiencies of light rays in the first coupling-out area 31 and the second coupling-out area 32 are improved, the light energy of the emergent light field of the diffraction light waveguide substrate is uniformly distributed, and the uniformity of image display brightness is provided.

On the basis of the above-described embodiment, the duty cycle of the grating in the coupling-out region and the grating tilt angle vary in a direction away from the coupling-in region. Parameters such as the grating inclination angle gamma and the duty ratio ff of the one-dimensional grating in the first coupling-out area 31 and the second coupling-out area 32 can be reasonably adjusted to change along the direction far away from the coupling-in area, so that the total reflection condition of light rays in the diffractive optical waveguide is matched, the diffraction efficiency in the first coupling-out area 31 and the second coupling-out area 32 is improved, and the purpose of uniform light energy distribution of an emergent light field of the substrate of the diffractive optical waveguide is achieved. Wherein the duty cycle ff = W/Λ.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, but that the features of the various embodiments of the invention may be combined with each other, in part or in whole, and may cooperate with each other and be driven in various ways that are technically desirable. Numerous and varied obvious variations, rearrangements, combinations and substitutions will now occur to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims (12)

1. A near-eye display device, comprising:

an apparatus main body;

an optical engine for projecting a light beam and disposed in the apparatus main body; and

a diffractive optical waveguide that is provided in the apparatus body and includes a waveguide substrate and a coupling-in area and a coupling-out area that are provided on at least one side of the waveguide substrate;

the waveguide substrate is provided with a first surface and a second surface which are parallel to each other, and the coupling-in area is used for coupling light beams into the waveguide substrate so that the light beams are transmitted to the coupling-out area in a total reflection mode between the first surface and the second surface; the coupling-out region comprises a first coupling-out region and a second coupling-out region; the second coupling-out region comprises a plurality of coupling-out sub-regions, at least two kinds of one-dimensional gratings with different grating directions are arranged in the second coupling-out region, one kind of one-dimensional gratings with at least two different grating directions is arranged in each coupling-out sub-region, and the second coupling-out region is used for expanding the pupil of the light beam and coupling out the waveguide substrate in a diffraction mode; the grating vector of the one-dimensional grating arranged in the first coupling-out region is the same as that of one of the one-dimensional gratings in the coupling-out sub-region; the first outcoupling region is for diffractively outcoupling the light beam out of the waveguide substrate.

2. A near-eye display device as claimed in claim 1 wherein the second out-coupling region comprises first and second oppositely disposed sides and a third side which is a region-bounding side of the first and second out-coupling regions;

the first side edge is close to the coupling-in area; the length of the first side is greater than that of the second side, and the width of the second coupling-out region is gradually reduced along a first direction; the third side edge is one or a combination of more of a straight edge, a curved edge and a zigzag edge, and the number of the third side edges is one or two;

the first direction is a direction in which the first side faces the second side, and the width of the second coupling-out region is a length in a second direction perpendicular to the first direction.

3. The near-eye display device of claim 1 wherein the second out-coupling area is regularly divided into a plurality of out-coupling sub-areas in one direction, or wherein the second out-coupling area is regularly divided into a plurality of out-coupling sub-areas in two different directions, or wherein the second out-coupling area is randomly divided into a plurality of out-coupling sub-areas.

4. A near-eye display device as claimed in claim 3 wherein the size of the out-coupling sub-region in at least one direction is smaller than the spot size of the light beam.

5. A near-eye display device as claimed in claim 3 wherein, when the second outcoupling region is regularly divided into a plurality of outcoupling sub-regions, the distance between the centers of two adjacent outcoupling sub-regions is:

wherein d is a central distance between two adjacent coupling-out subregions, n is a refractive index of the waveguide substrate, theta is an angle minimum value which can be resolved by human eyes, and lambda is a wavelength of a light beam projected by the optical machine.

6. A near-eye display device as claimed in claim 3 wherein when the second outcoupling region is regularly divided into a plurality of outcoupling sub-regions, each outcoupling sub-region comprises at least two outcoupling secondary sub-regions, and the grating directions of the outcoupling secondary sub-regions are different from each other.

7. The near-eye display device of claim 3 wherein when the second outcoupling region is randomly divided into a plurality of outcoupling sub-regions, the outcoupling sub-regions are Thiessen polygon partitions; dividing discrete points of the Thiessen polygon partition into intersection points of the light beams coupled into the optical waveguide substrate and the second coupling-out region; and/or the regularly marked reference points of the coupled-out sub-regions are offset by the resulting offset points.

8. The near-eye display device according to claim 1, wherein at least three different grating directions of one-dimensional gratings are arranged in the second coupling-out region, and a first one-dimensional grating of the at least three different grating directions is identical to a grating vector of the one-dimensional grating arranged in the coupling-in region; in the coupling-out sub-region of the second coupling-out region, the size in at least one direction of the coupling-out sub-region filling the first one-dimensional grating is smaller than the size in the direction of the coupling-out sub-region filling the remaining one-dimensional grating.

9. A near-eye display device as claimed in any one of claims 1 to 8 wherein the grating depth of the one-dimensional gratings within the first and second out-coupling regions respectively increases gradually in a direction away from the in-coupling region.

10. The near-eye display device of any one of claims 1-8 wherein a duty cycle and a grating tilt angle of the gratings in the out-coupling region vary in a direction away from the in-coupling region.

11. The near-eye display device of any one of claims 1-8 wherein a sum of grating vectors of the one-dimensional gratings in the in-coupling region and the out-coupling region is zero.

12. A near-eye display device as claimed in any one of claims 1 to 8 wherein the device body is embodied as a spectacle frame comprising a frame in which the diffractive optical waveguide is embodied as a display lens and two temples extending rearwardly from the left and right sides of the frame respectively.

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